Missing Band information for pretrained weights

### Issue

The [satlas weights](https://github.com/microsoft/torchgeo/blob/67fe198c78128e1162a241a783ac20ce350b52db/torchgeo/models/resnet.py#L527) have a `bands` entry in the metadata that lists the order and bands, for consistency and common api, it would be helpful to have that same metadata entry for all the other weights as well.

### Fix

Add `bands` info to metadata.

@paolofraccaro