Link to OSM Tile Usage Policy

[Adam-D-Lewis]

Hi, thanks for this great library.

it may be useful to add a link and a short note about OSM Foundation tile usage in the documentation somewhere. For convenience, here is the link I found to be most helpful (https://operations.osmfoundation.org/policies/tiles/), but there may be others.

[liodali]

for this package we're using native libraries in android and ios (web in soon) but i will add some notice about usage of tile