Getting certificate information from different lists or all (follow up from #610)

[jcps07]

In addition to what is requested in issue #610:

Update /dcl/pki/certificates in 1.4 so that it will ONLY return PAA, PAI and DAC if PAI and DAC have been uploaded in device attestation chain.
Implement another API that returns certificates regardless of PKI chain e.g. inclusive of DA or NOC.

To also consider getting certificate from Node Credentials based on Subject and/or SKID, so it'd be something like this:

API	Description
/dcl/pki/certificates	Query certificate by Subject and/or SKID in Device Attestation list (PAA, PAI, DAC) (#610)
/dcl/pki/all-noc-certificates	Query certificate by Subject and/or SKID in all Node Credentials list (RCAC, ICA, NOC). Not just from specific VID as /dcl/pki/noc-certificates/{vid}/{subject_key_id} does already
/dcl/pki/all-certificates	Query certificate by Subject and/or SKID from Device Attestation and Node Credentials (#610)

All of these will get matching cert(s) of different types of certs (PAA/PAI/DAC or RCAC/ICA/NOC or both), not just Roots.

[jcps07]

Note: The proposed query is still to be triaged. (/dcl/pki/all-certificates)

[robszewczyk]

One comment re: /dcl/pki/all-certificates -- documentation should be a bit more forward looking and make it clear that it should return all certificates. See #611 for a more forward looking certificate.proto

[hawk248]

/dcl/pki/all-certificates is it needed?
Use case: Given a SKI, allow user to query DCL to find out it it exists and what type it is.
This can be deferred. May be useful in the future.

DCL TT - OK to proceed implementation on this issue.