Replace name property by simple attribute

[huard]

Fix #63

[mishaschwartz]

Looks good to me. Is there a reason that the prefix and the name were linked before? Is there any value in trying to enforce that the prefix and the name are the same?

[huard]

I suspect not having this consistency might break some of the STAC stuff. Note that this consistency is ensured in the cordex_extension branch. I'll be able to port the changes to CMIP6 once we agree on the framework.

[fmigneault]

Is there a reason that the prefix and the name were linked before?

Yes!

Look at how many duplicate "cmip6" hard-coded values there are now.
It's very easy to forget one here and there. The previous approach allowed for anything to reference the same SchemaName. Changing it was a single-place edit.

The name class attribute replacement from a property to fix pystac interoperability is good, but I think a single "source of truth" should remain with SchemaName.