[bennu-admin] Improvements to the Domain Browser

  * Links now work properly
  * OID box is now properly updated
  * Better error handling
Removed deprecatd AuthenticationListener in favor of the synchronous version
Remove cross application server session invalidation
Removed accessibleGroups() feature
Reviewed group mechanics, separated persistent part from the group logic. Reviewed group language, now using antlr4 and solved all parenthesis issues. Improved error handling.
Add checksum to GenericFile
Create the concept of default file storage to handle unconfigured files
Extended file API to include an isAccessible(User user) method. New file type: GroupBasedFile that implements isAccessible with a Group
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