Draft: Resolve "Support OpenRC for Alpine packages"

Closes #1457.

• 37a8dcc2 fix agent pkg stub file

• e9bf1866 fix kea group name in alpine pkgs

• 71b4f9cc add openrc service files

• https://jenkins.aws.isc.org/job/stork/job/check-pkgs/330/ with https://jenkins.aws.isc.org/job/stork/job/check-pkgs/328/ as reference