add CLI flag `--onlyCategories`

[BioPhoton]

User story

As a developer sometimes I want to skip the execution of certain categories. E.g. to save time.

ATM there is no way to do this but comment them out in the code-pushup.config.ts

Acceptance criteria

• [ ] the CLI supports a terminal argument onlyCategories that is. used as string array that is undefined by default
• [ ] if onlyCategories is given execute only the provided categories form the core config
• [ ] notify the user similar to onlyPlugins

Implementation details

No response