At the moment we only have a basic version of a verify_chv commnad, but
in order to handle any CHV/PIN related situation we also need commands
to enable, disable, change and unblock CHV.
- fix verify_chv commnad: more distinct parameter names, better help
strings, correct pin code encoding and add external source lookup
- Add unblock_chv, change_chv, enable_chv and disable_chv commands
- add/fix related functions in commands.py
Change-Id: Ic89446e6bd2021095e579fb6b20458df48ba6413
Related: OS#4963