Add an option to ignore turned off transmitters

[Arielfoever]

when filter is set to "SSTV" we will see the UmKA-1 (57172). According to
https://db.satnogs.org/satellite/SDUV-9624-5611-1090-5908#transmitters, you can see it's off.

How about add a filter option to ignore these satlites without operational Filtered mode transmitter. in other words, if its SSTV transmitter is off then it will not been seen.

And, add an option to display disabled transmitters.

[rt-bishop]

Addressed in the recent v3.1.4 release. Although inactive tranceivers won't be shown at all for now. I may add a configurable option in the future to control this.