Updates to validating with Rego and CEL

[santoshkal]

This PR adds more validation features to Genval.

• Validation of Kubernetes resource manifests with Rego policies
• Validation of Terraform .tf resource files with rego policies - closes Implement Terraform resource validation using Rego Policies #8
• Validation of Kubernetes resource manifests with CEL policies. - Closes Add suport for validation using CEL - Common Expression Language #11
• Adds helper mode --showjson to show JSON representation of the input, this would help users write custom Rego/CEL policies. Closes Add a command to show JSON representation of generated Dockerfile #10
• Now Genval can validate/generate multiple Kubernetes/CRDs config files in cue mode. The generated manifests will be stored in ./output directory. - Coses Implement validation/generation of multiple JSON/YAML files in Cue mode #9

@MrAzharuddin

[chandu-intelops]

@santoshkal , resolve the conflicts please

[azar-writes-code]

@santoshkal , Please move the build file to root and make it executable anywhere.
Instead of ./genval , This should be genval [Command]

[azar-writes-code]

@santoshkal ,

Please look at the comment and add autocompletion as well and fix in the next PR.
While reviewing, got some conflicts, Please resolve and getback with the above mentioned changed required.

@chandu-intelops @devopstoday11 FYI

[santoshkal]

@santoshkal , resolve the conflicts please

got some conflicts, Please resolve and getback with the above mentioned changed required.

Thanks for the review @MrAzharuddin

Resolved the conflicts and is now ready to be merged.
@devopstoday11

[santoshkal]

@santoshkal , Please move the build file to root and make it executable anywhere. Instead of ./genval , This should be genval [Command]

Update the Makefile path for genval executable to cwd instead of ./bin/genval currently.
Thanks!