Fixes U4-2306
Fixes loading of MNTP.
FolderBrowser is now able to show multiple images on a single media item.
FolderBrowser only shows images and not containers.
Updating a few internal overloads as well as adding new ones to ensure backwards compatibility for events used by the tree.
Fixing issue with the Published/Unpublished/Saved/Pending Changes states shown in the content tree.
Fixes ContentType to ensure that ALL property type values get reset, not just ones assigned to a group.
Fixes logic in ContentTypeService to ensure that xml is re-generated when a property type alias is changed too.
Updating doc type create dialog to verify alias before saving.
Updating ContentTypeRepository to Mandate that the alias is not empty.
Fixes the cause for U4-1976
Refactoring ImportDocumentType dialog to import through the PackagingService.
Making a few corrections to the ProppertyGroup and PropertyType classes to support bulk saving.
updates especially when deleting one since we require all sorts of Ids from the object but the object will be deleted by the time
the request reaches other servers so instead we create a json payload to send to other servers which contains all information necessary
to refresh/clear the cache on the other servers. This will probably be the preferred way going forward to handle cache refreshing.
With this in place, when removing a conent type cache is removed based on events.
This also adds a 'class' generic argument constraint to the repository base classes to guarantee we can do null checks and then we also
fix a null check on RepositoryBase. Updates the Entity class to properly support tracking properties - this now allows us to determine if
an entity was new, which is now used to ensure we don't re-update all of the content cache when a new content type is created.
Have also changed the deletion and creation of document types to use the new API, this allows for a lot less processing and streamlining how
all cache is invalidated. Fixes the construction of a new Template and Content Type in the v6 api and ensures that default values are set - #U4-1972, #U4-1971
Adding a few new methods to the DataTypeService, which were needed for the import of DataTypes.
Adding bulk saving of templates.
Adding TopologicalSorter for sorting dependencies.
Implementing import of DataTypes and Templates.
Renaming the import test fixture for consistency after having creating the PackagingService.
