Improve OIDC web-app logout support

[sberyozkin]

Description

Keycloak and some other providers support RP-initiated logout - but many don't such as Auth0, Google, etc - they have their own custom ways of dealing with it.

If the logout is required but no end-session path is returned in a discovery doc - then if the user has set a logout-path property then quarkus-oidc should just delete a q_session (it does it now for RP initiated one and has also been discovered by @FroMage) and just redirect the user to the provided logout path.

In fact it can already work right now - but I believe the auto-discovery has to be disabled for a custom logout path to be taken into the consideration - so quite likely a very simple fix is needed

Implementation ideas

No response

[quarkus-bot]

/cc @pedroigor

[sberyozkin]

@FroMage I've had a look, quarkus.oidc.end-session-path as an absolute URL will redirect to the logout endpoint even if it is not returned in the discovery doc (and remove q_session) - but I think adding an option to add some extra logout params which are not part of the RP initiated spec but understood by Google and other providers which don't implement it would help