1002 Remove content items from folder
Folders - Rebuild libraries on content visibility update
Folders - Search for content IN a folder
Folders - Searching for folders and reindexing folders
Folders - Search for folder in principal’s library
Folders - Update a folder
Folders - Activities
Folders - Thumbnails
Folders - Augmenting content items when listing a folder
Folders - Specifying of folders when creating content items

Added a `folderIds` parameter to:
 * createLink
 * createCollabDoc
 * createFile

in oae-rest and updated the tests

Also added a test for the `text/plain` response type when
uploading files to the content create endpoint
Folders - Bugfix for updating a folder's library
Folders - Don’t (re)generate a folder preview if added content items have no previews
Folders - A folder content library is sorted on the content’s last modified timestamp

Also ensuring that new folder previews bust the cache
Folders - Deleting content should remove it from folders
Folders - deleteFolder & removeFolderFromLibrary TODO: more tests
Folders - Thumbnails for search results
Folders - Aggregate add-to-folder solely on folder
Folders - Reprocessing folder when content is deleted
Folders - Get deleting folders working for bugbash
Folders - Delete folder: search + more tests