Add coverage, gha, jenkins server, documentation and forum badges

Signed-off-by: Suraj Singh <[email protected]>

README.md

@@ -1,3 +1,11 @@
+[![codecov](https://codecov.io/gh/opensearch-project/OpenSearch/branch/2.1/graph/badge.svg)](https://codecov.io/gh/opensearch-project/OpenSearch)
+[![GHA gradle check](https://github.com/opensearch-project/OpenSearch/actions/workflows/gradle-check.yml/badge.svg)](https://github.com/opensearch-project/OpenSearch/actions/workflows/gradle-check.yml)
+[![GHA validate pull request](https://github.com/opensearch-project/OpenSearch/actions/workflows/wrapper.yml/badge.svg)](https://github.com/opensearch-project/OpenSearch/actions/workflows/wrapper.yml)
+[![GHA precommit](https://github.com/opensearch-project/OpenSearch/actions/workflows/precommit.yml/badge.svg)](https://github.com/opensearch-project/OpenSearch/actions/workflows/precommit.yml)
+[![Jenkins gradle check job](https://img.shields.io/jenkins/build?jobUrl=https%3A%2F%2Fbuild.ci.opensearch.org%2Fjob%2Fgradle-check%2F&label=Jenkins%20Gradle%20Check)](https://build.ci.opensearch.org/job/gradle-check/)
+[![Documentation](https://img.shields.io/badge/doc-reference-blue)](https://opensearch.org/docs/latest/opensearch/index/)
+[![Chat](https://img.shields.io/badge/chat-on%20forums-blue)](https://forum.opensearch.org/c/opensearch/)
+
 <img src="https://opensearch.org/assets/img/opensearch-logo-themed.svg" height="64px">
 
 - [Welcome!](#welcome)