fix!: Relying Party - discovery_uri, removal of DPoP and random fragment for request and response endpoints

[peppelinux]

this PR

• Closes How the request_uri brings the appropriate entropy #133
• introduces the discovery_uri endpoint where the Wallet Instance can provide its technical capabilities for interop, is inspired by request_uri extension openid/OpenID4VP#59
• remove DPoP and the provisioning of the Wallet Instance Attestation to the request_uri of the RP
• defines how to use #fragments to randomize the request_uri and the the response_uri endpoint, for the security of the RP. See Attestable and randomized redirect_uri and response_uri openid/OpenID4VP#73

[peppelinux]

See also
italia/eudi-wallet-it-python@fc4f7d9

[asharif1990]

I made a pass with a request to make some minor editorial changes to the MSC and the text.

[peppelinux]

two things to be done in this draft before making it a ready-to-be-merged PR:

1. abandon the discovery_uri and use the extention of the request_uri endpoint with the uri methods param, according to this: https://github.com/openid/OpenID4VP/pull/59/files
2. abandon the custom url-scheme and use onlt universal links; add also a box with the rationale behind this decision

[fmarino-ipzs]

I made an editorial change in the sequence diagram. I updated the plantuml link as a suggestion but the SVG must be updated accordingly.

[peppelinux]

Guys I merge this PR since it brings many important changes to be aligned, however the discussion on the OpenID4VP flows is still on the way, where discovery_uri (here) would be used instead of the request_uri_method

This means that we'll continue working with openid wg to achieve the definitive approach for that and then we'll open another PR about the presentation flow