listen_address should have an optional port and validate the host part

[anarcat]

Right now the listen_interface type enforces a port number, which is actually optional. it seems better to leave it out as it has a sane default too, registered in the prometheus port list and everything:

puppet-gitlab_ci_runner/manifests/init.pp

Line 86 in 7b0c340

Optional[Pattern[/.*:.+/]] $listen_address = undef,

it seems to me this should be some sort of hybrid type, a concatenation of Stdlib::Host and Stdlib::Port, with the latter optional. I'm not sure how we can do this without creating a new type, so maybe that's what should be done here, but then again I can't help but feel this might actually live better straight in stdlib. Surely someone else has had this problem before, right?