When having a running postgresql, the following error is produced:

```
$ nix run .#start-server 15
...
2023-08-19 15:25:26.476 -05 [1021103] LOG:  starting PostgreSQL 15.3 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 12.3.0, 64-bit
2023-08-19 15:25:26.476 -05 [1021103] LOG:  could not bind IPv6 address "::1": Address already in use
2023-08-19 15:25:26.476 -05 [1021103] HINT:  Is another postmaster already running on port 5432? If not, wait a few seconds and retry.
2023-08-19 15:25:26.476 -05 [1021103] LOG:  could not bind IPv4 address "127.0.0.1": Address already in use
2023-08-19 15:25:26.476 -05 [1021103] HINT:  Is another postmaster already running on port 5432? If not, wait a few seconds and retry.
2023-08-19 15:25:26.476 -05 [1021103] WARNING:  could not create listen socket for "localhost"
2023-08-19 15:25:26.476 -05 [1021103] FATAL:  could not create any TCP/IP sockets
2023-08-19 15:25:26.479 -05 [1021103] LOG:  database system is shut down
```

This is because it runs using the default 5432.

This changes the default port to 5435 to avoid conflicts.

Additionally:

- Parametrizes the pg default port for all configs(docker and local)
- Adds a port parameter to #start-client, e.g. `nix run .#start-client
  15 5433`