Handle resolution and tile loadingstrategy with user projection

[ahocevar]

This pull request fixes two problems with vector tile loaders:

• Resolutions need to be adjusted when units of user and view projection are different. This also fixes one of the problems described in Issues with vector loaders when using useGeographic() #10881.
• Assuming we always interact with tile grids in view projection, the tile grid passed to ol/loadingstrategy/tile needs to be in view projection.

The pull request adds a new example that shows how to use a tile loading strategy with useGeographic().

[mike-000]

The example needs Geographic in the title and tags to distinguish it from the existing example

[tschaub]

Thanks for the work on this, @ahocevar