Project groups

[tomolopolis]

Added a Project Groups feature

• ProjectGroups are a just a shortcut for creating multiple linked Annotation projects.
• Completing a project group admin form will now create X many ProjectAnnotateEntities entries, one for each 'annotator' selected in the annotator list. Admins will be added to all created projects.
• Once created ProjectGroup can be edited and these changes will be made to linked ProjectAnnotateEntities entries.
• Certain changes will not flow down, i.e. changes in annotators.
• Front end, home screen now can view ProjectGroups or individual lists of ProjectAnnotateEntities entries.
• refactored the admin module into a package.
• refactored the frontend project list table into a ProjectList component that is then re-used to render project lists for each ProjectGroup

TODOs:

• Document above feature
• Include in export. This will not changes the output format, only add the ProjectGroup for groupBys downstream.
• Extend usage of ProjectGroups to include gamification, IAA, Cohen's kappa metrics across project groups.
• ProjectGroups option should only appear for admin users on the home screen?