Disable rules for particular repos

[bcaller]

I don't want this to be abused, but for brave.com it would be helpful to ignore certain rules such as templated hrefs.

[thypon]

I was reflecting re this issue, and I feel it should not be the repository to control which rule is disabled, but the rule itself.
I think I'll add a metadata.allowlist and a metadata.blocklist containing regexes of repo names we want, or we don't want to apply rules on.

[bcaller]

The incentive for devs to just block random rules is too high haha? Only issue could be disclosure of private repo names in the public security-action repo, but we can choose to ignore this.

[thypon]

More like I want to address this issue too #47

Basically I need a rule that applies only to brave and brave-intl but none in brave-experiments