LayerSwitcher: add an option that rotates the map's View to a pre-defined value when a layer is made visible

[jacobwod]

We've recently added some layers containing photographies taken at a certain angle. These layers are "directed" in a specific direction, e.g. towards south. Since the map is always rotated with north at top, this leads to a strange perspective when such a layer is enabled.

User can of course rotate the View manually (Alt+Shift+Drag), but it'd really be preferable to rotate the View when such a layer is enabled.

[jacobwod]

Proposed solution triggers only when background layer visibility is changed. Given a set of four photographies taken in different directions, the results can be something like:

Skarminspelning.2024-01-17.kl.14.15.11.mov