Align mso_mdoc format identifier with language in OID4VP

[awoie]

OID4VCI ISO mDL section is not only about mDLs, it can cover any ISO mdocs. We should probably adapt the language that we have in OID4VP to make the section in OID4VCI less mDL-specific and show that it can be used with other doctypes as well.

[Sakurann]

Could you please do a PR on this?

[jogu]

Moved this to 1.0 as ISO want to see this as part of the 23220-3 alignment - reference on ISO side is AP_VCI_21