pgbackup.sh: Use psql options and SQL

postgres/files/pgbackup.sh

 #!/bin/sh
 
-for DB in $(sudo -u postgres psql -l 2>/dev/null | cut -d" " -f 2 | grep -v -- "---" | grep -v rows | grep -v '^[\t ]*$' | grep -v template)
+for DB in $(sudo -u postgres psql -t -q -A -c "select datname from pg_catalog.pg_database where not datname like 'template%';")
 do
 	sudo -u postgres pg_dump -o $DB | gzip -c -- > ${DB}.sql.gz
 done