Modify system to specify snmp communication protocol for each RSU

As of right now, the system does not specify an snmp protocol (4.1 / NTCIP1218) when making service requests to the ODE. This should be specified based on what the target RSUs are expecting the protocol to be.

This means that the system will need to keep track of which RSUs are running which protocols. The 'rsu' table seems like a good candidate location to store this information.