Tracker Checker: check UDP trackers

[josecelano]

Parent issue: #637

• Add check for announce request.
• Add check for scrape request.

[josecelano]

I think we should normalize tracker URLs from whatever format the user uses in the input to the full representation:

[udp|http/s]://[IP|domain]:[port]/announce
[udp|http/s]://[IP|domain]:[port]/scrape

cc @da2ce7