Demo configuration changes

Fixes a bug where instances spun up on different ports were joining the same cluster.

Support custom JDK version

Support custom JDK version

v4: Handle t param gracefully based on opensearch version (#5)

Handles start opensearch for older versions which don't allow for an initial admin password to be set during demo configuration setup.

Release v3

Allow port flexibility

Release v2

Adds support for changing the security config by API if security is enabled to support security-dashboards-plugin CI. Also disables watermark to help with test flakiness.

Release v1

Initial release of the start-opensearch github action. It downloads the min distribution of opensearch, optionally installs plugins, and starts the cluster, with or without security enabled.

Initial support for linux and windows only.