Enhancement: Exports for frequency restrictions

[CodeMeZone]

Feature description

Can you do something like rp-radio does for standalone for restrictedChannels?
https://github.com/FrazzIe/rp-radio
GivePlayerAccessToFrequency
RemovePlayerAccessToFrequency
GivePlayerAccessToFrequencies

Reason

Nothing really out there that does it like this.

[antond15]

Sounds great and usefull. I will implement it in a future update (v2 rewrite), but I don't have time for that currently.