Announcement-info support for welle-cli

[magiausde]

For monitoring stations with welle-cli it would be useful if mux.json could contain information about announcements.

Usually most stations transmit the Travel/Traffic announcement (like with RDS TA). I would like to check whether this announcement is active or when it last changed for a service.

[mpbraendli]

That's a good idea. Are you able to contribute this feature?