Resolve "Admin access to any course"

Closes #222 (closed), #197 (closed)

The following have been done:

Search courses:

• Add search courses page/functionality.
• Reorganize header based on admin functionality (Otto checked).
• Add course view page with information on its managers and editions (taken from Queue).
• Add links in job offer view page to parent course page and edition page.

Editions and accepted offers for existing (Head) TAs:

• Add edition view page with information on staff, job offers and contracts of the edition.
• Add functionality to add/remove staff from edition (as TAs/Head TAs and Teachers).
• If a TA/HeadTA is removed from an edition, they are rejected from all job offers in that edition (unless they have themselves rejected a job offer).
• If TA/HeadTA is detected in the edition but does not have a job offer a warning is shown at the top of the page.
• Buttons to add an accepted offer/or remove them from the edition for such students, have been added (for bulk and for single).

Teacher profile view for other teachers:

• If person viewed is not a student the payscale and TA training information is not shown.
• Programmes managed by the person is shown and editions of courses they are teaching.

Other:

• Changed permission for search people functionality (after speaking with Otto).
• Instead of the naming being "All Contract Requests" or "All Applications" I renamed them for consistencey

Testing:

• Added tests for new methods.

Images