Provide test vectors that exercise all functionality of the draft

[ounsworth]

We should provide test data for multiple EvidenceBundles and multiple EvidenceStatements. For completeness, we should provide samples of each of the 4 cases in Section 4.2:

4.2.1. Case 1 - Single Evidence Bundle
4.2.2. Case 2 - Single Evidence Bundle with Certificate Chain
4.2.3. Case 3 - Multiple Evidence Bundles each with Complete Certificate Chains
4.2.4. Case 4 - Multiple Evidence Bundles with Certificate Transmission Optimization

The actual evidence payload can be a stub, like a JWS with the content being the string "Evidence"; the point is to provide test vectors that exercise all functionality of the draft.

[ounsworth]

We have the Informative Reference:

[SampleData]
"CSR Attestation Sample Data", n.d., <https://github.com/lamps-wg/csr-attestation-examples>.

which allows us to continue producing samples at hackathons after this is published as RFC.