feat(jans-auth-server): add support for Identity Assertion JWT Authorization Grant

[yuriyz]

Description

feat(jans-auth-server): add support for Identity Assertion JWT Authorization Grant

https://www.ietf.org/archive/id/draft-ietf-oauth-identity-assertion-authz-grant-04.html

Test cases and code coverage

• Write unit test to cover added/changed code
• Update integration tests to cover added/changed code
• documentation

[coderabbitai]

🔗 Related PRs

#12848 - fix(jans-auth-server): put in access_token and id_token jwt only explicitly requested and allowed claims [merged]
#13922 - fix(jans-auth-server): added nested jwt into JWE for address claim tests #13895 [merged]
#14004 - feat(jans-auth-server): improved Invalid Request message for Authorization Endpoint #2775 [merged]
#14010 - test(jans-auth-server): fixed test providingIndividuallyRequestedEssentialAndVoluntaryClaims #14009 [merged]
#14086 - fix(jans-auth-server): added request_uri validation in AuthorizeAction.getRequestedClaims [merged]

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