Adds an API spec reference page for PostgresqlStandalone.
Follows: #35 and #37
Checklist
[x] Categorize the PR by setting a good title and adding one of the labels:
bug, enhancement, documentation, change, breaking, dependency
as they show up in the changelog
[x] PR contains the label area:operator
[ ] Link this PR to related issues
[x] I have not made any changes in the charts/ directory.
Summary
PostgresqlStandalone.Follows: #35 and #37
Checklist
bug,enhancement,documentation,change,breaking,dependencyas they show up in the changelogarea:operatorcharts/directory.