Define batch issuance for credentials without key binding

From the spec:

batch_credential_issuance: OPTIONAL. Object containing information about the Credential Issuer's support for issuance of multiple Credentials in a batch in the Credential Endpoint. The presence of this parameter means that the issuer supports more than one key proof in the proofs parameter in the Credential Request so can issue more than one Verifiable Credential for the same Credential Dataset in a single request/response.

batch_size: REQUIRED. Integer value specifying the maximum array size for the proofs parameter in a Credential Request. It MUST be 2 or greater.

This suggests that the requested batch size (from the wallet) corresponds to the number of elements in the proofs array in the request. However, if the wallet wants to obtain multiple copies of a credential without key binding, or if the issuer does not support credentials using key binding, this mechanism is not applicable.

Such a use case could still be useful, as even in the absence of key binding, there may be a risk of collusion if the same copy is used with different RPs.

Start by reviewing the quoted batch_credential_issuance and batch_size definitions in the specification, then read the existing comments on this issue. Define the requirements and boundaries for issuing multiple credentials without key binding, including how the request expresses the desired batch and how completion would be evaluated in the specification.