WIP tweak the header to offer a global and repository based navbar
Allow modification of a user's groups for a repo
Restyle the breadcrumb - reduce the height and tweak the shading
Fix tree icons being overridden... boo
Move Select a Repository to a top level navbar item with a dropdown selector;
Make new global menu reposponsive to viewport width
Display the repo_code in the flash message after select
Refactor helper method current_repo to lazy store the current repo object; hide some todo text on the user index;
Fix backend tests to as group listing endpoint is no longer paginated; Fix selenium tests to handle new menu frontend global/repo menu changes;
Fix exception when groups pulled back conflict with the session's repo and add a selenium test for good measure;
Merge pull request #365 from hudmol/43514117-groups-visible-on-user-forms

[Delivers #43514117] Allow setting of groups per user