Commitlint: Document commit scopes

[OndraM]

When using commit lint, scopes on the beginning of each commit message are enforced. However, there is nowhere any documentation which scopes should be used and when.
There is only configuration file, but without further documentation. This is very bad experience for people without previous conventional commits knowledge.

There should be a clear documentation of the scopes, similarly as commitzen provide:

(Or - we should preferably just use some common naming scheme, with slightest changes possible, and not invent our own.)