S2 names should use COG Identifier

[Jlrine2]

S2 names are currently given using the ESA identifier (e.g. S2B_MSIL2A_20200903T151809_N0214_R068_T22WEB_20200903T194353), we should change to the COG identifier (e.g. S2B_22WEB_20200903_0_L2A) because that's what Mark's pair list uses.

Also, consider validation of granule names and pairs here:

• both are valid names
• both are from the same mission

[jhkennedy]

I wonder if we should support both the ESA and COG identifiers, and translate ESA -> COG for processing

[jhkennedy]

Done in #33