Use custom commit types from cog.toml

[cococonscious]

Is your feature request related to a problem? Please describe.

Hi, I really like your work on this project so far, but there's one thing that keeps me from using it regularly: It doesn't take the custom commit types I've configured in cog.toml, the configuration file from cocogitto, but requires another config file, with often the exact same entries.

Describe the solution you'd like

I'd like koji to parse the custom commit types I configured in cog.toml, perhaps specified through a configuration option (like "parse custom commit types from the cog.toml in the current repository if available").

Describe alternatives you've considered

None.

Additional context

Obviously, the description that's configurable through kojis configuration file would be missing from the commit types declared in cog.toml. I thought of 3 ways to solve this. The first one is to just use the changelog_title property which should be available on every declared commit type. The second one is to omit it all together and just have it say "Custom type declared in cog.toml" or similar. The last one, which can be used together with the first two proposals, is to advice users to add a description (or similarly named) property to their commit types, which would just be ignored by cocogitto but could be used by koji.

As it's currently not possible to remove a commit type in cocogitto, the current descriptions in koji can still be re-used in my opinion, only non-standard custom commit types would need to be handled differently.
Edit: I opened a PR on cocogitto to allow disabling default commit types. If this is ever implemented, koji should also allow disabling commit types in the same way as cocogitto, provided that this PR will be implemented until then. cocogitto/cocogitto#386