Foreman Maintain

Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=2029807

Description of problem:
foreman-maintain service fails for external Postgres service when no psql utility is installed with message unable to connect to the remote database.

Version-Release number of selected component (if applicable):
Satellite 6.10.1.1
rubygem-foreman_maintain-0.8.21-1.el7sat.noarch

How reproducible:
Always

Steps to Reproduce:
1. Configure repos for satellite, and install satellite package.
2. Install and configure Postgres on rhel as per documentation¹
3. Run the installer as mentioned in documention¹ to configure satellite with external DB, which fails with BZ 2029793
4. Check the status of the external PostgreSQL service, which fails with the following message,

1. foreman-maintain service status --only postgresql
   Running Status Services ================================================================================
   Get status of applicable services:

Displaying the following service(s):
postgresql (pulpcore), postgresql (candlepin), postgresql (foreman)
/ displaying postgresql (pulpcore)
postgresql (pulpcore) is remote and is DOWN.
Unable to connect to the remote database.
See the log (/var/log/foreman-maintain/foreman-maintain.log) for more details.
/ displaying postgresql (candlepin)
postgresql (candlepin) is remote and is DOWN.
Unable to connect to the remote database.
See the log (/var/log/foreman-maintain/foreman-maintain.log) for more details.
/ displaying postgresql (foreman)
postgresql (foreman) is remote and is DOWN.
Unable to connect to the remote database.
See the log (/var/log/foreman-maintain/foreman-maintain.log) for more details.
/ All services displayed [FAIL]
Some services are not running (postgresql (pulpcore), postgresql (candlepin), postgresql (foreman))
--------------------------------------------------------------------------------

Actual results:
a message like, "Unable to connect to the remote database, see logs"

Expected results:
Message something like, "The psql command not found. Make sure the system has a psql utility installed."

Additional info:
This BZ² has provided a similar fail-safe option for backup/restore when psql is unavailable with methods like "psql_cmd_available?" for Postgres and "mongo_cmd_available?" for Mongo.

[1] https://access.redhat.com/documentation/en-us/red_hat_satellite/6.10/html/installing_satellite_server_from_a_connected_network/performing-additional-configuration#using-external-databases_satellite
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1921295