[feature] Favourite stations

[recursiveribbons]

Currently, to listen to a specific station, the index must be reloaded. A common use-case for the module is to listen to a small subset of stations. There should be no need to reload the index for this.

When a station is marked as a favourite, it can always be assumed to exist, without loading the index.

[TheLastProject]

I made a start with this on df784a7

TODO:

• Remove favourite (c0eaa2c)
• Add favourite from list (instead of only when tuned in)

For now, if you want to remove a favourite, manually edit _user_favourites.txt in ~/.config/pext/modules/pext_module_radio/.

[TheLastProject]

Implemented favourites removal in c0eaa2c