Allow Employees to also download their Company's CompanyVC

[jfelixh]

This will allow the use of EmployeeVC without the need for a public list of CompanyVC. The Employee simply presents both, essentially presenting the entire VC chain.

[jfelixh]

Clarify the final strategy used to establish the trust chain (trust anchor -> COMPANY -> employee). The company credential (or at least some metadata) has to be known to the verifier in some way.

Broadly two solutions:

1. Publish company credentials.
2. Let employees store and also present their company's credential.