Add buttons for Bing StreetView and Yandex Panoramas

[tsmock]

I will write a patch for these if there is interest for them. The user would still have to follow the UI for seeing the imagery, but at least they would be nearby.

Bing URL format:
https://www.bing.com/maps?cp={latitude}~{longitude}&lvl={zoom}

Yandex URL format: [done in cf47fb4]
https://yandex.com/maps/?ll={longitude}%2C{latitude}&z={zoom}