Remove toolbar for non staff users
Add tests
Change test name
Draft implementation of ExtensionToolbar
Add documentation for ExtensionToolbar
Loosen up a bit toolbar permission checking
Removed unused imports
fix documentation. Add item in the changelog (to be changed to 3.1 if no 3.0.6 will be released)
Merge pull request #3421 from yakky/feature/no_toolbar_for_no_staff

Remove toolbar for non staff users
Merge pull request #3454 from yakky/feature/model_placeholder_staff

Show Structure mode for staff users
Merge pull request #3453 from yakky/feature/extensions_toolbar

Add extension toolbar simplified API
Merge remote-tracking branch 'upstream/develop' into develop