Bike Shed `vcHolders`

[aljones15]

Currently this test depends on endpoints with the tag vcHolders in a property named vcHolders in implementations.

There are quite a few problem here:

1. vcHolder does not explicitly state the suite the endpoint uses, supports, or a tag referring to a test suite.
2. The property vcHolder conflates selective disclosure with holder a term used for the recipient or holder of an issued VC.
3. It adds an additional tag needed in configuration

Some proposals

1. remove the property vcHolder from implementations manifests in favor of something else such as derivers
2. change the tag to match the suite the deriver is being used in