Discipline annotations

[fbacall]

• Allows projects and workflows to be annotated with scientific disciplines.
• Propagates disciplines set on a project down to workflows under that project (if they do not already have any disciplines set).
• Refactors how default policies/licenses are handled, fetching them with an AJAX call rather than storing a mapping on the page.
• Moves investigation/study select field to the "manage" pages of studies/assays.

[stuzart]

a couple of minor comments, but also I do wonder if we now need Topics anymore, as this is just a duplication with a smaller set of terms. Alternatively the extra terms could be added to Topics. Having both seems a bit confusing and weird.