amsr2 l1b reader also match amsr2 l2 products

[TAlonglong]

the amsr2 l1b reader also match amsr2 l2 products

l1b filename: GW1AM2_202004171159_065B_L1SNBTBR_2220220.h5
l2 filename: GW1AM2_202004161432_090B_L2SNSSWLB3300300.h5

I'm looking into add reading of the L2 SSW product and this needs some small updates to the l1b reader to make it work.

Should I update the l1b reader or should I create a amsr2_l2 reader mostly the same as the l1b reader?

If I create a new reader we need to update the l1b reader to only match L1 data

[TAlonglong]

Just a quick example of the SSW data

[djhoese]

I think my preference would be to make a separate reader but just use the same python code (point the YAML to the same python module). If needed, subclass the python class in to a new amsr2_l2.py module.