Passphrase for main key

Description

Right now onionbalance-config --help announces a --password flag, but this is unsupported.

Tasks

• Decide whether this feature should be implemented.
• If to implement, then go ahead.
• If not to implement (now), then:
  • Remove ConfigGenerator.get_master_key_passphrase().
  • Remove the --password from parse_cmd_args().
  • Keep this issue open for a while, maybe awaiting for offline keys.