5463-allow-absolute-postgresql-ssl-path-configuration.yml

- Users who set an absolute file path for their postgres SSL certificate
  will see `gitlab-ctl reconfigure` fail because the addition of Patroni
  in commit 5c1d80c2 changed to using `File.join` for building the path
  versus `File.absolute_path`
- Adds tests to ensure that if a user sets `ssl_cert_file` or
  `ssl_key_file` to an absolute path that it will retain the behavior of
  using that exact path

Closes https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/5463



Signed-off-by: Robert Marshall <rmarshall@gitlab.com>