use multi stage docker build.

[Poonai]

Now, all docker builds use the --no-cache flag to make sure a new binary is being sent to the docker image.

But, it's increasing the build time a lot.

On a local machine, it takes more than 5 mins to build the image. So, explore other opportunities, to decrease build time

reference: https://github.com/poonai/inspektor/blob/main/build_dataplane_docker.sh