Add + document vendor specific control commands
- Clock tuning control (factory / manual / locked to GPS / maybe even locked to E1 ?)
- E1 'tick' control ( master / slave )
- E1 feature control ( Things like CRC4 enable / auto-E bits / ... )
- % Done changed from 10 to 20
- https://gerrit.osmocom.org/c/osmo-e1-hardware/+/21775 contains an ice1usb_proto.h file that describes the control commands for Rx/Tx configuration and for general capability inquiry.