Qualify `ufw` commands

This pull request qualifies the `ufw` commands in order to ensure that they run
without error during a Puppet run. Previously, the command would fail to run as
the exec was unqualified, and Puppet could not find the binary:

```
Error: Parameter unless failed on Exec[ufw-allow-tcp-from-any-to-any-port-22]: 'ufw status | grep -E "22/tcp +ALLOW +Anywhere"' is not qualified and no path was specified. Please qualify the command or specify a path.
```

Puppet refuses to trust that the $PATH of the shell from which a Puppet run is
started is correct. It therefore demands qualified `exec` types.