forest nodes are unreachable over p2p

**Issue summary**

While internally exposed, also with DO firewall, a netfilter firewall is still blocking inbound connections. This needs to be set during the droplet [bootstrap](https://github.com/ChainSafe/forest-iac/blob/main/tf-managed/modules/forest-droplet/bootstrap.bash.tftpl):

```
ufw allow 12345/tcp
```

Deploy and test the connectivity on a fresh instance.
```
telnet
```
must connect.
```
❯ telnet 159.223.21.201 12345
Trying 159.223.21.201...
Connected to 159.223.21.201.
Escape character is '^]'.
```

**Other information and links**