Add id field to ExpireApiKeyRequest and DeleteApiKeyRequest messages.
This allows API keys to be expired or deleted by their database ID
in addition to the existing prefix-based lookup.
Updates #2986
We currently do not have a way to clean up api keys. There may be cases
where users of headscale may generate a lot of api keys and these may
end up accumulating in the database. This commit adds the command to
delete an api key given a prefix.
