[FEATURE] Use docker image's entrypoint by default

[patelsmit32123]

Is your feature request related to a problem?

Currently, startup command defined in the operator code contains plugin installation and the entrypoint command. If someone provides their own image, then they also need to add their own command as well via spec otherwise operator would use same entrypoint as the public docker image.

What solution would you like?

We should let k8s use entrypoint defined in the image and install plugins via a separate init container. Need to figure out how to install plugins via init container and make it visible to main os container

[patelsmit32123]

I would like to work on this if request is accepted.