Log warning if postgres user password no longer matches OPERATOR_PASSWORD.

[davissp14]

If a user manually alters the postgres user password and does not update the associated OPERATOR_PASSWORD the cluster will not boot properly.

This PR adds a warning indicating the issue and a hint on how to resolve it.

2023-02-24T23:29:30Z app[39080777f24487] den [info]postgres | 2023-02-24 23:29:30.786 UTC [597] FATAL:  password authentication failed for user "postgres"
2023-02-24T23:29:30Z app[39080777f24487] den [info]postgres | 2023-02-24 23:29:30.786 UTC [597] DETAIL:  Connection matched pg_hba.conf line 8: "host all all ::0/0 md5"
2023-02-24T23:29:30Z app[39080777f24487] den [info]WARNING: `postgres` user password does not match the `OPERATOR_PASSWORD` secret
2023-02-24T23:29:30Z app[39080777f24487] den [info]HINT: Use `fly secrets set OPERATOR_PASSWORD=<password> --app shaun-password-test-2` to resolve the issue
2023-02-24T23:29:30Z app[39080777f24487] den [info]failed post-init: failed to establish connection to local node: failed to connect to `host=fdaa:0:2e26:a7b:d828:8945:f3e0:2 user=postgres database=postgres`: failed SASL auth (FATAL: password authentication failed for user "postgres" (SQLSTATE 28P01)). Retrying...

[DAlperin]

fixes #139