This includes the basics that we need to get type checking for pydcs
calls.
Type checking has been disabled in a few monkey-patching cases. Patches
ought to be sent upstream (or in the case of dead unit tracking,
replaced with a better model).
The loadout case actually could (and previously did) hide bugs from the
type checker, since mypy was smart enough to see that we were removing
None from the input it assumed that the member was non-optional, but
later modifications could cause null values, and since those came from
the UI mypy couldn't reason about this. This meant that mypy assumed the
type could not be optional and wouldn't check that case.
We're missing a lot of checking right now. Most of it requires
additional cleanup. For now I've enabled what I could and will follow up
to clean up and enable more checking.
