Add Check Discovery

[scott-wilson]

Let's say that a rigger is about to publish their rig, or an animator is about to publish their animation. It would be nice if the checks API would look like this (In Python):

import my_studio_checks

context = StudioAsset("/myAsset")

checks = my_studio_checks.gather(context)

for check in checks:
    result = pychecks.run(check)

I suspect that behind the scenes, the my_studio_checks might look like this:

# my_studio_checks.py

import pychecks

_CACHE = None


def gather(context):
    _init_checks()
    
    return _CACHE.gather(context)


def _init_checks():
    global _CACHE

    if _CACHE:
        return

    _CACHE = pychecks.DiscoveryRegistrar()
    _CACHE.register(_is_context_rig, _generate_rig_checks)


def _is_context_rig(context):
    if not isinstance(context, StudioAsset):
        return False

    return context.asset_type() == "rig"


def _generate_rig_checks(context):
    return [
        RigCheckA(context),
        RigCheckB(context),
        RigCheckC(context),
    ]