Feature Request: Ability to sync stream groups so that channels are added AND removed when the M3U gets updated

[Jakyrian]

Is your feature request related to a problem? Please describe.
Providers often change what streams (channels) are available, so it'd be convenient if the sync option could have a further option (or perhaps it should just be how the sync option works) to automatically create/remove channels from a SG when the M3U refreshes.

Describe the solution you'd like
See above

Describe alternatives you've considered
N/A

Additional context
Originally requested by ExploitPanda on Discord here

[seansusmilch]

This is my exact use case as I am scraping for streams that will only be on for a few hours. Once a stream is over, I remove it from my http endpoint and would like it to be automatically removed from my channel list in StreamMaster as well. Currently, it does not get pruned and stale/dead m3u streams remain in the list.

[mitch91175]

This would be pretty amazing to have. Could be part of stream management for SM. The question would be what happens if the stream is temporarily unavailable then becomes available again. Will you have to manually add the stream back to the SG. Also with programs like Emby the stream will still be in the Live TV section (unless you setup all stream as .strm and they are also removed from the OnDemand which will also remove them from the library).