Add security cops from gitlab-styles

[baelter]

WHY are these changes introduced?

We use rubocop-gitlab-security that is deprecated. gitlab-styles superseeds it but we don't want that dependency since it will control which rubocop version we can use.

WHAT is this pull request doing?

Copying cops we want for gitlab-styles into this gem.

HOW can this pull request be tested?

Specs

[baelter]

Could not get all specs to pass. Timeboxing for now. Will return in the future if no one beats me to it.

[walro]

Can try to take look here if you are swamped :)

[baelter]

See if you understand why the specs fail, don't spend a lot of time on it though.

[walro]

Yeah, failed in my timebox too. I tested with Ruby 3.1 and 3.2 and tried to mimic their version constraints. Also checked spec_helper if there was something that we were missing. Looked briefly at issues and history for gitlab-styles without spotting anything apparent. Also noted that the only two cops that don't pass are the "legacy ones" from rubocop-gitlab-security (PublicSend and JsonSerialization), the newer specs seem to pass. Didn't have time to dig into details there.