Update Status List 2021 references in light of spec changes

[rhofvendahl]

There are some significant changes in the works for the w3c status list spec (repo here), including:

• Renaming StatusList2021Entry to StatusListEntry
• StatusList2021Credential to StatusListCredential
• StatusList2021 credential type to StatusList
  (see: chore: update title and urls to contexts w3c/vc-bitstring-status-list#69)
• https://w3id.org/vc/status-list/2021/v1 to https://www.w3.org/ns/status-list/v2

When/if these changes are made official it will be necessary to update all such references in interop specs and tests.

This issue first discussed in PR #560

[nissimsan]

Similar to #566 , focus on the upstream test suite first.

[rhofvendahl]

@nissimsan as with #566, I'm unclear on how the jose-cose repo relates to status list 2021 references?

[rhofvendahl]

Closing, no longer makes sense given v2