Add UDP protocol option for the port check extension

[dlopes7]

A customer requested and paid us to add UDP support.

There is no universal way to test UDP, we are imitating what netcat does here, which is:

1. Send an empty UDP Datagram
2. Wait for a server response with a 2 second timeout
3. If we receive a response (unlikely) - TEST OK
4. If we receive a Connection exception - TEST FAILED
5. If we receive a timeout exception, we ping the HOST.
6. If both the timeout and ping fail - TEST FAILED, if the ping passes - TEST OK

This is not a reliable test, because UDP is not a reliable protocol

[myieye]

Sounds well thought through! 👍