Minimize Dockerfile , Separate Docker image for worker and API

[kshitijrajsharma]

Currently Dockerfile is very minimal , it is bigger in size , Both worker and API are using the same docker image ! This works for start , Plan is to create a minimal version of docker image so that it won't have big size . API and Worker should be using different image. This also includes clear definition of requirements for both worker and API . Frontend docker needs to be minimal as well
cc : @omranlm