Able to use project components as golang library

[dmvolod]

I am impressed by the functionality of this project as a helm plugin. Thanks to the community for supporting it.
As developer, I would like to use part of the component functions, i.e. manifests diff, etc. in OSS project. But now, part of the required functions, i.e. cmd.genManifest is private and inside the cmd package which is related to the CLI.

I would like to contribute to make them public and resudable. I hope this will not affect the functionality and maintainability of the project.