Refactor generator code

[varshaprasad96]

Currently, the project uses declares flags in a separate package, whose values need to be copied to the generator. An alternative approach would be:

• Remove flag package
• Rename Flags struct to Options
• Move Options struct into pkg/generator
• Bind flags directly to an Options instance
• Have the Generator work directly against Options (to avoid having to copy)
• Simplify package path for the generator: Clientset wrapper for kcp #1 (comment)

Note: These options need to be passed down to all the generators.

[xrstf]

I am now rewriting the entire code-generator, based on the k8s architecture.