Remove osm_adsbx background map

[WhoAmI0501]

Hi, i would like to recommend to change the default background map of tar1090 from the AdsbExchange OpenStreetMap mirror to the normal OpenStreetMap tile servers. Further, i'd like to recommend to fully remove the osm_adsbx background map from tar1090.

My reasons for that proposal are:

• Due to the recent activities around adsbx, any implementations or dependencies should be reduced
• I heared about some DoS attacks or something against adsbx - understandable, but some friend told me, that their tar1090 background map is not loading properly (bad for UX)
• The adsbx OpenStreetMap mirror is using cloudflare, which is imho a no-go regarding to privacy and self-hosting stuff

[wiedehopf]

I'm happy for openstreetmap to have less traffic for as long as this works.

I don't care about your cloudflare concerns, everyone who cares can just select a different map layer.

This is not a dependency as you can just change the layer if there is an issue.