Add REST endpoint for CifData

[ltalirz]

• add /cifs/... endpoints
• add test
• replace hardcoded endpoint info by properly formatted dynamically generated list

[ltalirz]

@giovannipizzi
Is there some policy on adding REST endpoints?
I.e. do we simply add what we need as we go along or do you want to limit the number of available end points?

[giovannipizzi]

I think it is ok to add them, but maybe good to sit down at some point and discuss what the policy should be for new ones, to avoid too many and confusion in the future. Only think, is this documented? It would be good to have an example for it and mention this class in all parts needed, here http://aiida-core.readthedocs.io/en/latest/restapi/index.html#examples

[ltalirz]

@giovannipizzi

It would be good to have an example for it and mention this class in all parts needed

I've now added a table with a complete list of available resources that is linked to the respective aiida classes.
For the moment I haven't added an example as there are currently no examples for the derived Data types (at some point this page would explode...).

I noticed that a lot of the basic AiiDA functionality is not part of the API doc.
I always wondered why you are trying to add things to the API-doc manually instead of relying on sphinx-apidoc. Is there a particular reason?
This would also force developers to write (& correct) documentation as they go.

[giovannipizzi]

I'm perfectly ok to use sphinx-apidoc, and actually I also agree it's better - I still think that having a general, short page describing what the API tries to achieve in general, and then pointing the the sphinx doc for the various endpoints, is useful.
Feel free to convert the current doc to apidoc, or to have an issue on what is missing in the docs.