Add Traffic Ops Client Functions for all nullable objects and ReqInf

[rob05c]

Many TO Client objects are missing Nullable objects, and missing returning ReqInf.

We need to go through and add all of these, and mark functions missing either as // Deprecated.

Nullable objects are necessary to distinguish missing from empty values, and ReqInf is necessary for clients to get the IP (which is important to users, if there's an error or unexpected behavior, and TO is behind a GSLB).

[rawlinp]

Duplicate of #2546