Support OIDC Mutual TLS

[sberyozkin]

Fixes #19634.

This PR does the following:

• updates OIDC Tls configuration group to support the keystore options (named exactly as those in Vert.x HTTP) - a few more options can be added like supporting individual cert and key files, not sure it will be necessary but can be easily added if required during the next iteration
• updates integration-tests/oidc to use KeycloakX and MTLS (not sure it should also be supported with Dev Services - it requires configuring 4 stores so probably not worth it)
• updates the docs
• cleans up some code I prototyped earlier in the test Keycloak server code - which was actually never used and assumes the use of WildFly

@pedroigor I recall during the earlier discussions you were mentioning a dedicated MTLS option - but since we already have TLS where the truststore can already be configured I thought it would make sense to use it and add the keystore options

[sberyozkin]

Hi @gsmet I'm proposing a backport to 2.7 since, even though it is a new feature, all it does it allows to configure the OIDC keystore options and reads the store (same way as in VertxHttpRecorder and it is tested). If you agree it is not too sensitive then please consider backporting

[quarkus-bot]

Failing Jobs - Building ff4880b

Status	Name	Step	Failures	Logs	Raw logs
✔️	JVM Tests - JDK 11
✖	JVM Tests - JDK 17	Build	Failures	Logs	Raw logs

Failures

⚙️ JVM Tests - JDK 17 #

- Failing: extensions/reactive-oracle-client/deployment integration-tests/hibernate-search-orm-elasticsearch integration-tests/jpa-mssql and 1 more
! Skipped: integration-tests/reactive-oracle-client 

📦 extensions/reactive-oracle-client/deployment

✖ Failed to execute goal io.fabric8:docker-maven-plugin:0.38.1:start (docker-start) on project quarkus-reactive-oracle-client-deployment: I/O Error

📦 integration-tests/hibernate-search-orm-elasticsearch

✖ Failed to execute goal io.fabric8:docker-maven-plugin:0.38.1:start (docker-start) on project quarkus-integration-test-hibernate-search-orm-elasticsearch: I/O Error

📦 integration-tests/jpa-mssql

✖ Failed to execute goal io.fabric8:docker-maven-plugin:0.38.1:start (docker-start) on project quarkus-integration-test-jpa-mssql: I/O Error

📦 integration-tests/jpa-oracle

✖ Failed to execute goal io.fabric8:docker-maven-plugin:0.38.1:start (docker-start) on project quarkus-integration-test-jpa-oracle: I/O Error

[sberyozkin]

The failing tests 100% do not have anything to do with this PR, all the security tests have passed, so I'll go ahead with the merge, thanks