Related to #34183, #27393, #1208

Use case

I have an image that I want to use as a marker icon on Google Maps with scaling ratio 3.5.
There is no way to achieve this currently unless I provide mipmaps for it (didn't try playing with fractional ratios though so it might not work at all)

Proposal

1. Make use of ImageConfiguration.devicePixelRatio in BitmapDescriptor.fromAssetImage
2. Preferably also offer a sync version of this function as there's nothing async required for this and async marker load will require a consecutive setState and widget rebuild.