UI: Introduce Internal namespaces for classes not part of documented API

Description

Introduce Internal namespaces for classes that are not part of the documented API. Many of these classes have a public interface that is the public API.
Breaking changes
The following classes were removed from the public API and implementation moved into sub namespace ".Internal".

EPiServer.Cms.Shell.UI.CmsModuleViewModel
EPiServer.Cms.Shell.UI.Json.ActivityActionConverter
EPiServer.Cms.Shell.UI.Json.BlockDataConverter
EPiServer.Cms.Shell.UI.Json.CategoryListConverter
EPiServer.Cms.Shell.UI.Json.ContentAreaConverter
EPiServer.Cms.Shell.UI.Json.ContentDataStoreModelConverter
EPiServer.Cms.Shell.UI.Json.IContentConverter
EPiServer.Cms.Shell.UI.Json.LinkItemCollectionConverter
EPiServer.Cms.Shell.UI.Json.UrlConverter

EPiServer.Cms.Shell.UI.Search.BlockSearchProvider
EPiServer.Cms.Shell.UI.Search.ContentSearchProviderConstants
EPiServer.Cms.Shell.UI.Search.ContentTypeQuery
EPiServer.Cms.Shell.UI.Search.FileSearchProvider
EPiServer.Cms.Shell.UI.Search.PageSearchProvider

EPiServer.Cms.Shell.UI.UI.ActionResults.TransferResult

EPiServer.Cms.Shell.UI.UI.CompositeViews.HomeView
EPiServer.Cms.Shell.UI.UI.CompositeViews.MediaView

EPiServer.Cms.Shell.UI.UI.Controllers.EPiAboutController
EPiServer.Cms.Shell.UI.UI.Controllers.FileUploadController
EPiServer.Cms.Shell.UI.UI.Controllers.GeographicController
EPiServer.Cms.Shell.UI.UI.Controllers.GeographicLocationController
EPiServer.Cms.Shell.UI.UI.Controllers.JsonErrorHandlingAttribute
EPiServer.Cms.Shell.UI.UI.Controllers.PropertyRenderController
EPiServer.Cms.Shell.UI.UI.Controllers.UserProfileController
EPiServer.Cms.Shell.UI.UI.Controllers.VisitedCategoriesController
EPiServer.Cms.Shell.UI.UI.Controllers.VisitorGroupMembershipController
EPiServer.Cms.Shell.UI.UI.Controllers.VisitorGroupsController

EPiServer.Cms.Shell.UI.UI.Controllers.Preview.DefaultMediaPreviewController
EPiServer.Cms.Shell.UI.UI.Controllers.Preview.ImageEditController
EPiServer.Cms.Shell.UI.UI.Controllers.Preview.ImagePreviewHandler
EPiServer.Cms.Shell.UI.UI.Controllers.Preview.MediaEditController
EPiServer.Cms.Shell.UI.UI.Controllers.Preview.MediaPreviewHandlerBase
EPiServer.Cms.Shell.UI.UI.Controllers.Preview.VideoEditController
EPiServer.Cms.Shell.UI.UI.Controllers.Preview.VideoPreviewHandler

EPiServer.Cms.Shell.UI.UI.Controllers.Reports.EPiBrokenLinksController

EPiServer.Cms.Shell.UI.UI.CmsMenuProvider
EPiServer.Cms.Shell.UI.UI.ContentDataMetadataProvider
EPiServer.Cms.Shell.UI.UI.ContentDataModelAccessorCreator
EPiServer.Cms.Shell.UI.UI.ContentMetaDataPropertiesInjector
EPiServer.Cms.Shell.UI.UI.GroupedMetaDataRegistry
EPiServer.Cms.Shell.UI.UI.MetaDataPropertyInfo
EPiServer.Cms.Shell.UI.UI.ViewModeMenuProvider

EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.ContentActivitiesNotReadyQuery
EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.ContentActivitiesReadyToPublishQuery
EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.ContentActivitiesRejectedQuery

EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.ContentQueryProvider
EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.ContentRestorePointQuery
EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.ContentSearchQuery
EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.DefaultContentQueryHelper
EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.EditingInProgressQuery
EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.GetBlockRootChildrenQuery
EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.GetContentByPermanentLinkQuery
EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.RecentlyChangedQuery
EPiServer.Cms.Shell.UI.UI.Rest.ContentQuery.SearchDeletedContentQuery

EPiServer.Cms.Shell.UI.UI.Rest.CategoryStore
EPiServer.Cms.Shell.UI.UI.Rest.ChannelStore
EPiServer.Cms.Shell.UI.UI.Rest.CmsContentContextResolver
EPiServer.Cms.Shell.UI.UI.Rest.CompositeValidationError
EPiServer.Cms.Shell.UI.UI.Rest.ContentDataStore
EPiServer.Cms.Shell.UI.UI.Rest.ContentLanguageInformationResolver
EPiServer.Cms.Shell.UI.UI.Rest.ContentReferenceStore
EPiServer.Cms.Shell.UI.UI.Rest.ContentStoreModelCreator
EPiServer.Cms.Shell.UI.UI.Rest.ContentStructureStore
EPiServer.Cms.Shell.UI.UI.Rest.ContentTypeStore
EPiServer.Cms.Shell.UI.UI.Rest.ContentVersionStore
EPiServer.Cms.Shell.UI.UI.Rest.DefaultContentTypeAdvisor
EPiServer.Cms.Shell.UI.UI.Rest.DefaultLocalAssetNameGenerator
EPiServer.Cms.Shell.UI.UI.Rest.DisplayOptionsStore
EPiServer.Cms.Shell.UI.UI.Rest.InUseNotificationStore
EPiServer.Cms.Shell.UI.UI.Rest.LanguageStore
EPiServer.Cms.Shell.UI.UI.Rest.MissingContentLanguageInformationResolver
EPiServer.Cms.Shell.UI.UI.Rest.SiteStructureStore
EPiServer.Cms.Shell.UI.UI.Rest.VisitorGroupStore
EPiServer.Cms.Shell.UI.UI.Rest.WasteBasketStore
EPiServer.Cms.Shell.UI.UI.Rest.XFormStore

EPiServer.Cms.Shell.UI.UI.Rest.Models.CategoryViewModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.ChannelStoreModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.ContentDataContext
EPiServer.Cms.Shell.UI.UI.Rest.Models.ContentLanguageBranchModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.ContentTypeViewModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.ContentVersionViewModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.ContentViewModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.DisplayOptionModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.ExtendedVersionStatus
EPiServer.Cms.Shell.UI.UI.Rest.Models.InUseNotificationViewModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.SiteLanguageModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.VisitorGroupViewModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.WasteBasketViewModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.XFormViewModel

EPiServer.Cms.Shell.UI.UI.Rest.Models.Transforms.ContentDataModelBasePropertiesTransform
EPiServer.Cms.Shell.UI.UI.Rest.Models.Transforms.ContentDataModelBaseTransform
EPiServer.Cms.Shell.UI.UI.Rest.Models.Transforms.ContentDataStoreModelTransform
EPiServer.Cms.Shell.UI.UI.Rest.Models.Transforms.ContentVersionFilter
EPiServer.Cms.Shell.UI.UI.Rest.Models.Transforms.ModelTransformContext
EPiServer.Cms.Shell.UI.UI.Rest.Models.Transforms.PopulatePageDataModel
EPiServer.Cms.Shell.UI.UI.Rest.Models.Transforms.StructureStoreModelTransform

EPiServer.Cms.Shell.UI.UI.UIDescriptors.BlockUIDescriptor
EPiServer.Cms.Shell.UI.UI.UIDescriptors.ContentDataUIDescriptor
EPiServer.Cms.Shell.UI.UI.UIDescriptors.ContentUIDescriptor
EPiServer.Cms.Shell.UI.UI.UIDescriptors.ContentUIDescriptorProvider
EPiServer.Cms.Shell.UI.UI.UIDescriptors.FolderUIDescriptor
EPiServer.Cms.Shell.UI.UI.UIDescriptors.ImageUIDescriptor
EPiServer.Cms.Shell.UI.UI.UIDescriptors.LinkItemUIDescriptor
EPiServer.Cms.Shell.UI.UI.UIDescriptors.MediaFileUIDescriptor
EPiServer.Cms.Shell.UI.UI.UIDescriptors.PageUIDescriptor
EPiServer.Cms.Shell.UI.UI.UIDescriptors.VideoUIDescriptor

EPiServer.Cms.Shell.UI.UI.UIDescriptors.ViewConfigurations.Compare.AllPropertiesCompare
EPiServer.Cms.Shell.UI.UI.UIDescriptors.ViewConfigurations.Compare.Compare

EPiServer.Cms.Shell.UI.UI.UIDescriptors.ViewConfigurations.ContentListing
EPiServer.Cms.Shell.UI.UI.UIDescriptors.ViewConfigurations.FormEditing
EPiServer.Cms.Shell.UI.UI.UIDescriptors.ViewConfigurations.OnPageEditing
EPiServer.Cms.Shell.UI.UI.UIDescriptors.ViewConfigurations.Preview

EPiServer.Cms.Shell.UI.Workspace.Committers.ContentDataCommitArguments
EPiServer.Cms.Shell.UI.Workspace.Committers.ContentDataCommitter