Investigate AsyncUDP Library

[shortbloke]

Investigate AsyncUDP to replace looping to check for new UDP packets.

• Check platform support/portability
• Check existing udp library doesn't have async methods
• Believe changes would require registering a callback. Would need to implement for SNMPGetRequest and SNMPGetResponse

[JoaoVitorMaia]

Regarding the architecture, the callback registration and non synchronous response, needs to behave like that or something like this:
char routerSerialNumber = snmp.getString(oid, timeout);
DateTime routerUptime = snmp.getTimeTicks(oid, timeout);
would be and improvement?