[BUG] Generating certificates should be optional for ./gradlew run

[owaiskazi19]

What is the bug?

With the current changes merged to main #619. To run helloWorld from here the SSL certificates needs to be generated. Generation of this certificates should be optional and not impact the current ./gradlew run.

Exception in thread "main" OpenSearchSecurityException[Error while initializing transport SSL layer from PEM: OpenSearchException[Unable to read /Users/kazabdu/opensearch-sdk/config/certs/extension-01.pem (/Users/kazabdu/opensearch-sdk/config/certs/extension-01.pem). Please make sure this files exists and is readable regarding to permissions. Property: ssl.transport.pemcert_filepath]]; nested: OpenSearchException[Unable to read /Users/kazabdu/opensearch-sdk/config/certs/extension-01.pem (/Users/kazabdu/opensearch-sdk/config/certs/extension-01.pem). Please make sure this files exists and is readable regarding to permissions. Property: ssl.transport.pemcert_filepath];
        at org.opensearch.sdk.ssl.DefaultSslKeyStore.initTransportSSLConfig(DefaultSslKeyStore.java:395)
        at org.opensearch.sdk.ssl.DefaultSslKeyStore.initSSLConfig(DefaultSslKeyStore.java:230)
        at org.opensearch.sdk.ssl.DefaultSslKeyStore.<init>(DefaultSslKeyStore.java:152)
        at org.opensearch.sdk.NettyTransport.getNetty4Transport(NettyTransport.java:83)
        at org.opensearch.sdk.NettyTransport.initializeExtensionTransportService(NettyTransport.java:109)
        at org.opensearch.sdk.ExtensionsRunner.run(ExtensionsRunner.java:769)
        at org.opensearch.sdk.sample.helloworld.HelloWorldExtension.main(HelloWorldExtension.java:82)
Caused by: OpenSearchException[Unable to read /Users/kazabdu/opensearch-sdk/config/certs/extension-01.pem (/Users/kazabdu/opensearch-sdk/config/certs/extension-01.pem). Please make sure this files exists and is readable regarding to permissions. Property: ssl.transport.pemcert_filepath]
        at org.opensearch.sdk.ssl.DefaultSslKeyStore.checkPath(DefaultSslKeyStore.java:785)
        at org.opensearch.sdk.ssl.DefaultSslKeyStore.resolve(DefaultSslKeyStore.java:208)
        at org.opensearch.sdk.ssl.DefaultSslKeyStore.initTransportSSLConfig(DefaultSslKeyStore.java:365)
        ... 6 more

> Task :run FAILED

How can one reproduce the bug?

1. Clone the repo
2. Do a ./gradlew run

What is the expected behavior?

./gradlew run should run smoothly. Security settings should be commented and documented if requires to be run.

What is your host/environment?

MacOS

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.