Make integration tests configurable to use different containers

[sothawo]

Currently tests and integration tests are separated by having a Junit @Tag with the value "integration-test" set on the test classes for integration tests. These tags are evaluated in the maven setup for the test and verify executions.

Integration tests start a Testcontainer with an Elasticsearch instance at the beginning of the integration tests and shut it down at the end.

In order to be able to develop Spring Data Elasticsearch to support different clients / systems like Elasticsearch or Opensearch, we need to be able to further add attributes to the integration tests defining which Testcontainer should be used. These attributes should be defined when starting the test, and should be evaluated when the tests are run.

It must be possible to disable tests or testclasses based on the chosen approach, for example if a test covers functionality that is provided by one system but not the other.