Our current recommended pg_service setup to connect to the DB replica is:
```
[swh-replica]
dbname=softwareheritage
host=somerset.internal.softwareheritage.org
user=guest
port=5433
```
But that needs to setup manually such file.
We should puppetize this and install it by default on our swh nodes so that user can simply execute:
```
swhuser@swhnode $ psql service=swh-replica
```
for example to connect to the db replica.
Related T1234#33001
Note:
As a first incremental step, i'll only reference the guest user (read-only access).
Shout out if we need also write access.