Add -q flag to psql calls to suppress 'INSERT 0 1' etc

Closes #6

When running psql commands to insert rows in the database, psql normally
returns an message about what it did, eg "INSERT 0 1" if it inserted a
row. This can be suppressed with -q . Several of the scripts use psql
commands to get primary keys from the database, inserting the row if
necessary. This can lead to the host id variable in the script being set
to 'INSERT 0 1 <thehostid>' which causes problems when this variable is
used in other SQL commands.

This always used to work; I suspect the thing that changed is our
upgrading to Postgres 16 on the backup servers, but I'm struggling to
see how as Postgres 13 seems to behave the same for me.