Update revocation method from https://w3c-ccg.github.io/vc-status-rl-2020/ to https://www.w3.org/TR/vc-bitstring-status-list/

[onthebreeze]

Most current VC implementations use https://www.w3.org/TR/vc-bitstring-status-list/ for revocation status. To better support VCkit interoperability we should change the default VC status method to https://www.w3.org/TR/vc-bitstring-status-list/