[BUG] Implement a mechanism to add OpenSearch node to ConnectionManager Map

[owaiskazi19]

What is the bug?

OpenSearch source node should be add to ConnectionManager map. Otherwise the node won't start

org.opensearch.transport.NodeNotConnectedException: [][127.0.0.1:4532] Node not connected
        at org.opensearch.transport.ClusterConnectionManager.getConnection(ClusterConnectionManager.java:204) ~[opensearch-3.0.0-SNAPSHOT.jar:3.0.0-SNAPSHOT]
        at org.opensearch.transport.TransportService.getConnection(TransportService.java:784) ~[opensearch-3.0.0-SNAPSHOT.jar:3.0.0-SNAPSHOT]
        at org.opensearch.transport.TransportService.sendRequest(TransportService.java:681) ~[opensearch-3.0.0-SNAPSHOT.jar:3.0.0-SNAPSHOT]
        at transportservice.RunPlugin.handleIndicesModuleRequest(RunPlugin.java:134) ~[main/:?]
        at transportservice.RunPlugin.lambda$startTransportService$2(RunPlugin.java:239) ~[main/:?]
        at org.opensearch.transport.RequestHandlerRegistry.processMessageReceived(RequestHandlerRegistry.java:98) [opensearch-3.0.0-SNAPSHOT.jar:3.0.0-SNAPSHOT]
        at org.opensearch.transport.InboundHandler$RequestHandler.doRun(InboundHandler.java:443) [opensearch-3.0.0-SNAPSHOT.jar:3.0.0-SNAPSHOT]
        at org.opensearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:792) [opensearch-3.0.0-SNAPSHOT.jar:3.0.0-SNAPSHOT]
        at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:50) [opensearch-3.0.0-SNAPSHOT.jar:3.0.0-SNAPSHOT]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) [?:?]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) [?:?]

This can be done during the transport handshake.

How can one reproduce the bug?

Steps to reproduce the behavior.

What is the expected behavior?

A clear and concise description of what you expected to happen.

What is your host/environment?

Operating system, version.

Do you have any screenshots?

If applicable, add screenshots to help explain your problem.

Do you have any additional context?

Add any other context about the problem.