Remove UVM endorsement descriptor hardcoding at Start and Recovery

[achamayou]

I think this is all the change we need, because the UVM endorsement descriptor is already passed to /create and /create writes the descriptor to the ledger/KV.

• Add a test checking that the descriptor is in the initial Tx for both Start and Recover
• CHANGELOG entry

[cjen1-msft]

To double check this PR moves the check of UVM endorsements from the startup path to the open decision by the consortium members.

So what root of trust is added to the kv, is this part of the open decision?

[achamayou]

@cjen1-msft yes, that's exactly right. The did/feed/svn of the UVM endorsements validated at startup is captured in public:ccf.gov.nodes.snp.uvm_endorsements in the KV, where it can be audited before open, and forms the initial value of the set that is used to validate new joiners going forward.

The recovery initial tx gets to set this again, on the basis of endorsements found on recovery node startup.