Documentation & Swig Overhaul

[FFroehlich]

Documentation:

• [ ] add documentation for enum classes

Swig:

• [ ] Add more ignores for classes/functions that are more confusing than helpful for the general user (like amici.amici.backtraceString)

[dweindl]

• [x] add documentation for ExpDataView/ReturnDataView to sphinx

[dweindl]

* [ ]  add documentation for enum classes

That's gonna be a bit of a pain. This will require AST-walking to extract the enum member documentation (some example), unless SWIG will start using typing.Annotated at some point. Documentation of the enum itself (not it's members) won't be accessible, as far as I can see.