Update dockerfile

[parthyadav3105]

Update and optimize Kupenstack Dockerfile.

[parthyadav3105]

Previously, KupenStack was using helm2 cli and was required to install multiple dependencies. This is not required now as KupenStack has moved to helm3 golang client. Now, in container we only need the KupenStack binary file. The KupenStack binary also requires ca-certificates dependency for helm3 golang client.

Desired container image:

A minimal container image with the KupenStack binary and ca-certificate dependency.

How to verify:

Step 1: Successful image build

Step 2: Use the new image to deploy KupenStack on the Kubernetes cluster. Use existing manifest files. It should deploy OpenStack without failures.