[Feature]: Persist radio settings filter in URL for sharing map state

**Platform:** Other

**Description:**
integrate radio settings filter into the URL so sharing the map by URL brings the currently filtered radio settings with it (this is important in regions that are moving to 500 kHz)

**Discord:** https://discord.com/channels/1463383723327356992/1466576085960626186/1547981627475493015

Submitted by: mixmastermouse (Discord)