This installs a pgbouncer instance on the belvedere machine.
The setup matches closely the one already installed on both prado and belvedere (mostly the db connections for now only bounces to swh on prado, swh-deposit, swh-scheduler, swh-scheduler-updater to belvedere itself, and then keep the initial number of connections, the type of connection trust, already setuped there etc...).
Once deployed, the differences i saw will be:
- the current /etc/pgbouncer/pgbouncer.ini is complete and commented (probably installed through a template file then got adapted). The new one will only be a subset of what's defined here (without comments).
- the actual /etc/pgbouncer/userlist.txt is plain and the password is human-readable, it will no longer be the case. The password will be hashed (md5 though).
- dropped the default host * default connection. I prefer we have failure connections when something is not defined.