Allow to customize JWT token algorithm for OIDC and OIDC client

[sberyozkin]

This PR follows #21192 - makes it possible to customize a token signature algorithm by using quarkus.oidc.credentials.jwt or quarkus.oidc-client.credentials.jwt scoped signature-algorithm property to make it more flexible as opposed to relying on a global property.

We have already have 3 separate JWT authentication oidc-client and oidc tests so rather than creating a new one I just modified the existing one - the secret key which is used has length 512 bits or more - so it just worked - I can confirm that if trim this key a bit then I see

org.jose4j.lang.InvalidKeyException: A key of the same size as the hash output (i.e. 512 bits for HS512) or larger MUST be used with the HMAC SHA algorithms but this key is only 336 bits

PR itself is very simple - just adds a signature-algorithm property and updates the JWT JWS builder if it is set