[Openid-specs-ab] Issue #1839: define Deferred Credential Endpoint metadata (openid/connect)

[Kristina Yasuda]

New issue 1839: define Deferred Credential Endpoint metadata
https://bitbucket.org/openid/connect/issues/1839/define-deferred-credential-endpoint

Kristina Yasuda:

> **TODO**: Deferred Credential Endpoint metadata needs to be defined in OID4VCI spec.

from the security analysis: [openid / connect / Pull Request #468: First draft of OpenID 4 VC Security Analysis — Bitbucket](https://bitbucket.org/openid/connect/pull-requests/468#Lopenid-4-vc-security-and-trust-1_0.mdT828)

\(personally, I am in favor of merging deferred credential issuance functionality into the credential/batch endpoint\)