Switch to enabling patroni by default with new patroni role

What does this MR do?

Switch to enabling patroni by default with new patroni role Throw an error early in reconfigure if someone is trying to use repgmr with PG12

Related issues

Part of #5888 (closed)

Closes: #5921 (closed)

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• Pipeline is green on dev.gitlab.org if the change is touching anything besides documentation or internal cookbooks
• trigger-package has a green pipeline running against latest commit

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for the GitLab Chart opened

Test Plan

• Test fresh install patroni role - get patroni
• Test fresh install explicit repmgr - get PG 12 error
• Test fresh install explicit repmgr with PG 11 - gets repmgr

changelogs/unreleased/repmgr-guardrails.yml

+---
+title: Switch to enabling patroni by default with postgresql role
+merge_request: 4851
+author:
+type: changed