[Extensions] Create Transport action to initialize extensions

[owaiskazi19]

Is your feature request related to a problem? Please describe.
Coming from initialize extensions API.
This API initializes an extension by making a connection from OpenSearch to the extension. Since the API is on the http thread and the connection here is done on transport thread. The API should return the response received from the transport thread if the connection is successful or if it fails.

Describe the solution you'd like
Create TransportAction, a request and execute the connection to the exension through NodeClient.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

[owaiskazi19]

#8029