Improve checks

[Douile]

• Adds .actrc so CI actions can be tested locally
• Adds testing for variants of features so changes that break feature sets like disabling games can be caught
• Adds more of the CI tests to pre-commit

[Douile]

An unintended side-effect of this is that it spams the discord webhook.

[CosminPerRam]

The Discord messages aren't a problem, I'll ask @mmorrisontx to change webhook settings.