Expand API to allow modifications

[jonblack]

Currently the API only provides two functions:

1. annotations: gets the list of annotations for the given pdb id
2. entries: gets all entries in a given databank and state (PRESENT, VALID, etc)

There are two generic use cases for the API:

1. Allow other services to update whynot when an entry is missing by providing the annotation. This would primarily be used by the databank update scripts. It has the knock on effect that whynot wouldn't need to crawl and annotate itself anymore, which performs poorly and often lags behind the real state of the databanks.
2. Allow humans to manually update entries. Currently this is done by placing files in a comment and uncomment folder on the server, which is not ideal.

I also think this is a good opportunity to standardise the API using a hypermedia format like JSON-API and consolidate the API endpoints.

To Do

• Consider security implications. How exposed is the API?
• Propose endpoints