This mirrors changes to GCP IPI in #3544
The infra id of the clusters on GCP was reduced to 12 in #2088 because
we couldn't handle the hostname seen by rhcos machine to be greater than
64.
More details on this are available in
https://bugzilla.redhat.com/show_bug.cgi?id=1809345
now since BZ 1809345 is fixed by openshift/machine-config-operator#1711
and openshift/cluster-api-provider-gcp#88 the installer can relax the
restriction on the infra-id to match the other platforms.
Why is it important?
On GCP all resources are prefixed with infra-id, which currently is 12
chars with 6 chars used by random bit, leaving only 6 chars from cluster
name. This causes trouble associating the cluster to jobs in CI as most
of the identifyable characters are dropped from the resource names in CI
due to this restriction.
Also because of the previous restriction, only one char are used from
pool's name, making is higly likely to collide in cases there are more.
Before this change, the GCP UPI workflow hard coded the zones in the
bootstrap and control-plane templates. It assumed every region had zones
$REGION-{a,b,c}. However, in some regions this is not the case.
This change adds the zone(s) as parameters to the templates and updates
the docs accordingly. The list of zones is now fetched from gcp, and
then used to populate the templates.
