List all database names

You can generate a list of PostgreSQL database names.

Switch to the pe-postgres user by running:
```
sudo su - pe-postgres -s /bin/bash
```
Open the PostgreSQL command-line by running:
```
/opt/puppetlabs/server/bin/psql
```
To list the databases, run: \l
To exit the PostgreSQL command line, run: \q
To log out of the pe-postgres user, run: logout