Optimize OIDC code flow to do one less redirect when the original path has to be restored

[sberyozkin]

OIDC CodeAuthenticationMechanism can restore the original request path, for example:

1. User does GET /web-app/service
2. Redirect path is configured as /web-app
3. The user, after authenticating, is redirected back to Quarkus to /web-app
4. Now, before proceeding with the code to token exchange, the user is redirected to /web-app/service thus restoring the original request URI; to implement it, a custom pathChecked query is added, so it is not ideal
5. Finally, after the code has been exchanged, another redirect follows, dropping code and state and other non-custom query parameters

So, step 4 is redundant, it adds to the cost of processing and also returns code and state back to the browser because the code flow has not completed yet.

As such this PR drops step 4 and the original path, if needed, will be restored as part of the last step

I had to fix a few tests because they were written around the flow involving step4.

[sberyozkin]

@pedroigor Hey, I've spent a lot of time trying to make it work and came to the conclusion it is that is impossible to avoid some hacks :-) and as such I'm going to close this PR, but the good news is, while refactoring the code to make it work I've managed to get rid of one local redirect where the original path is restored :-). so I'll be working on re-focusing this PR going forward

[sberyozkin]

@pedroigor Hey Pedro
I've completely re-focused the PR on optimizing the redirects, please see the description, it drops one redundant redirect which can only a good thing for the performance and the security of the flow too :-)