[FEATURE] Add a Swagger playground where APIs can be invoked against

[VachaShah]

OpenSearch API specs publishing was setup in PR #75 and #76. Proposing some enhancements for the published specs:

• Once we implement spec versioning, have an option for versioned specs [PROPOSAL] Publish versioned API specs #84
• Implement the Try it out button to use a custom server link (localhost or a custom server endpoint)
• Custom UI

[dblock]

I recommend doing at least minimum versioning earlier than later, i.e. publishing specs under a product and major version folder (e.g. OpenSearch/2.x).

[dblock]

There's a good idea here to have a playground that lets you try an API, renamed.

[dblock]

Actually https://opensearch-project.github.io/opensearch-api-specification/ has a way to try APIs, but that doesn't work because there's no actual OpenSearch, I'll open a new bug on this.