Drivers - INS - Applanix - POSMV - Decode Group 3 SNR values for L1 and L2

 Use Case:

We wish to track L1/L2 SNR values to warn of antenna failures (so need to consider elevation as well).

Suggested Improvement:

Add the option to decode Group 3 ( ICD - P17 onwards). Its the info in table 8 I am interested in.