Intuitive use of rigctld/rotctld

[bjorgan]

Currently have to specify e.g. --rotctld-host=[HOST] in order to enable connection to rotctld (and rigctld).

Additional possibilities (in addition to current CLI options):

• Detect availability of rotctld/rigctld automatically (and add possibility for disabling entirely)
• Add configuration files
• In-program configuration

Do an assessment on whether any of the above makes this more inconvenient and cumbersome or not.

rigctld autodetection will be problematic, won't know what to choose for uplink and downlink, but might be good to rethink this a bit.

[bjorgan]

Fixed in f0bac33 by revising the CLI flags and adding a settings screen.