Default to PostgreSQL 14 in Omnibus for new installs

Summary

Soon Add support for PostgreSQL 14 (&9065 - closed) we will make PG14 the default version for new installs and upgrades.

Requirements

• Verify Upgrade procedure for PostgreSQL 14 on G... (#7768 - closed) is validated and completed before starting any of following.
• For new installs of Omnibus GitLab, PostgreSQL 14 is used by default
• Users can opt to use PostgreSQL 13 during a new install

• Upgrades of existing deployments will stay on PostgreSQL 13 unless the user manually upgrades the PostgreSQL version

Issue used when defaulting to PG 12: #5509 (closed)