feat: conventional commits v2

[kevgo]

Here comes v2 of the new system to enforce conventional commit style on pull requests. Big thanks to @zepatrik for providing detailed feedback about what didn't work with v1, providing pointers to a better solution, and even going the extra mile and submitting a possible upstream fix! 🚀

V2 finally provides the right abstractions that Ory needs (I think):

• a centralized Ory-specific set of default titles and scopes
  • most repos can use those and don't need any custom config files at all
• a generic workflow definition that can be pushed to all repos as often as we want without overriding customizations
• ability for individual repos to override particular settings via a separate file
• ability to add titles and scopes to the existing sets

One problem with all previous versions was that the set of allowed titles and scopes was stored redundantly in every repo (in .github/semantic.yml). This is hard to maintain, for example when adding a new default scope we have to update this file in every repo. This problem no longer exists in v2.

Please pay extra attention to the set of default titles and scopes. I'm not sure what I have so far is the correct set that is used by all Ory repos. Thanks!

This is used by ory/ci#94.

[kevgo]

This is ready for re-review. Please merge only after ory/ci#94.