PostgreSQL parameters managed by Patroni should rely on values set in `postgresql[]`

Summary

Patroni has a set of parameters to manage postgresql replication. This is currently defined in patroni['postgresql'][]. We should consider this as an implementation detail and rely on existing defined parameters in main postgresql[].

Proposal

Reuse parameters from postgresql[] to set supported patroni['postgresql'][] parameters.

We should also review any documentation that mentions patroni['postgresql'][] and suggest only to set them via postgresql[].

We should additionally consider whether to deprecate patroni['postgresql'][] entirely before GA.

References