wago: added modules 750-464 & 750-473

Closes #1911 (closed)

Contribution from @sallazda

• basic handling of module 750-464

    "750-464": [0, 0, 4, 0, 4, 4, "thc", "4 Channel Resistance Measurement Input"],

• complete handling of module 750-473

    "750-473": [0, 0, 2, 0, 2, 2, "fs4-20", "2 Channel 4/20mA Input"],