default `postgresql_hba_entries` are outdated for postgresql-15

[gclawes]

The default values includes with postgresql-15 on Debian 12 are:

# Database administrative login by Unix domain socket
local   all             postgres                                peer

# TYPE  DATABASE        USER            ADDRESS                 METHOD

# "local" is for Unix domain socket connections only
local   all             all                                     peer
# IPv4 local connections:
host    all             all             127.0.0.1/32            scram-sha-256
# IPv6 local connections:
host    all             all             ::1/128                 scram-sha-256
# Allow replication connections from localhost, by a user with the
# replication privilege.
local   replication     all                                     peer
host    replication     all             127.0.0.1/32            scram-sha-256
host    replication     all             ::1/128                 scram-sha-256

The provided defaults set in postgresql_hba_entries are outdated in comparison:

# Host based authentication (hba) entries to be added to the pg_hba.conf. This
# variable's defaults reflect the defaults that come with a fresh installation.
postgresql_hba_entries:
  - {type: local, database: all, user: postgres, auth_method: peer}
  - {type: local, database: all, user: all, auth_method: peer}
  - {type: host, database: all, user: all, address: '127.0.0.1/32', auth_method: "{{ postgresql_auth_method }}"}
  - {type: host, database: all, user: all, address: '::1/128', auth_method: "{{ postgresql_auth_method }}"}

In particular:

• md5 appears to be the default if ansible_fips is false, which contradicts the more secure default of scram-sha-256
• replication entries are missing.

As mentioned in #76, it would be useful to be able to append entries to the defaults, instead of overriding.