Add rededge1,2,3 to common names

[m-mohr]

It's a bit weird that the common name rededge has 3 bands included for S2, which is not ideal if you try to identify bands based on the common names.
The great repository Awesome Spectral Indices splits the rededge into 3 parts: Red Edge 1, 2 and 3.
I'd propose to add these three in addition.

[matthewhanson]

Discussed in STAC sprint

@emmanuelmathot to create draft PR for v2.0 of this extension which will remove eo:bands for compliance with upcoming STAC 1.1 - see radiantearth/stac-spec#1254