Data Model Documentation refresh for v0.8.0

[marshalc]

After Issue #158 got sidetracked, recreating the original task here.

Update the documentation, specifically the pydoc generated content.

Try to have it pick up the choices or limits applied to various parameters so that Virginia can see the list of expected values.

[marshalc]

Note to self: Sphinx had an update recently, so remember to monkey patch it again as it will likely still be broken... https://gist.github.com/marshalc/327fc737ce0557a253c0c3d57f679292

[marshalc]

Remember to improve the docstrings with information such as in https://docs.djangoproject.com/en/1.10/ref/contrib/admin/admindocs/#documentation-helpers

[marshalc]

Reworking conf.py:

• Added translation and original label name to fields
• Need to find a way to stop it displaying fields as properties with long summary like: "A wrapper for a deferred-loading field. When the value is read from this object the first time, the query is executed."

[marshalc]

Translation is always active, so haven't found a way to get the untranslated name once a language is activated. Thus need to decide whether the en-GB label text is best, or if the en-DB debug text would be best.

[marshalc]

Updated again for the 0.9.0 task list