Add generated ECDH key provider

[justin-tay]

Adds a key provider to generate ECDH realm keys for use for the ECDH-ES, ECDH-ES+A128KW, ECDH-ES+A192KW and ECDH-ES+A256KW JWE algorithms.

Closes #23596

[ghost]

Unreported flaky test detected, please review

[ghost]

Unreported flaky test detected

If the below flaky tests below are affected by the changes, please review and update the changes accordingly. Otherwise, a maintainer should report the flaky tests prior to merging the PR.

org.keycloak.testsuite.ui.account2.WelcomeScreenTest#resourcesTest

Keycloak CI - Account Console IT (firefox)

org.awaitility.core.ConditionTimeoutException: Assertion condition defined as a org.keycloak.testsuite.util.URLAssert URL expected to begin with: https://localhost:8543/auth/realms/test/protocol/openid-connect/auth ; actual URL: https://localhost:8543/auth/realms/test/account/#/resources within 10 seconds.
	at org.awaitility.core.ConditionAwaiter.await(ConditionAwaiter.java:167)
	at org.awaitility.core.AssertionCondition.await(AssertionCondition.java:119)
	at org.awaitility.core.AssertionCondition.await(AssertionCondition.java:31)
	at org.awaitility.core.ConditionFactory.until(ConditionFactory.java:985)
...

Report flaky test

org.keycloak.testsuite.x509.X509BrowserCRLTest#loginSuccessWithCRLSignedWithIntermediateCA3FromTruststore

Keycloak CI - FIPS IT (strict)

java.lang.RuntimeException: Could not create statement
	at org.jboss.arquillian.junit.Arquillian.methodBlock(Arquillian.java:313)
	at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
...

Report flaky test