Add ODFERestTestCase to common utils

[jmazanec15]

Is your feature request related to a problem? Please describe.
It appears that we have several instances of ODFERestTestCase implementations across plugin repos:

1. https://github.com/opensearch-project/k-NN/blob/main/src/test/java/org/opensearch/knn/ODFERestTestCase.java
2. https://github.com/opensearch-project/anomaly-detection/blob/main/src/test/java/org/opensearch/ad/ODFERestTestCase.java
3. https://github.com/opensearch-project/alerting/blob/11aafbe26189a474349d24c161ca956c044c7b63/alerting/src/test/kotlin/org/opensearch/alerting/ODFERestTestCase.kt

This base test class is meant to ensure ODFE compatibility. Each implementations seems slightly different. We had a test failure related to this case here: opensearch-project/k-NN#214. Given all of this, it appears that this class is a good candidate to move to common-utils.

[engechas]

Hi @jmazanec15 - is this issue still relevant with the introduction of OpenSearchRestTestCase in core?