Make IdToken feature complete

[nanderstabel]

Description

Make the IdToken struct fully feature complete as mentioned here: #17 (comment)

Also, implement a builder pattern either specifically for IdToken and/or for a Token enum with (at least) the IdToken(IdToken) and VpToken(VpToken) variants. They should directly map to the already existing ResponseType enum that's being used in the SiopRequest struct.

Motivation

The IdToken should be fully feature complete in order to be 100% conform to the SIOPv2 specification.

The IdToken can have several different kind of claims, such as the openid standard claims, jwt registered claims, and other claims. The following specifications need to be followed:

• Section 2 of Openid Core and the flow-specific ID Token requirements
• Section 11 of SIOPv2

Resources

• Section 2 of Openid Core and the flow-specific ID Token requirements
• Section 11 of SIOPv2

To-do List

No response