Add linters to enforce code consistency

[rakeshgm]

To maintain consistent code quality and enforce best practices, ramenctl should adopt linting tools. Adding linters will ensure a standardised coding style across the project. This could also server as first step towards introducing CI to validate the code changes.

Linters

golangci-lint

Start with this configuration:
https://github.com/nirs/kubectl-gather/blob/main/.golangci.yaml

It was taken from Cobra, and some linters were disabled due to issue in the current code. We want to enable the disabled linters in this repo.

If the current code does not pass the lint job you can disable the linters until it pass. In the next step enable each linter by fixing the issues in the current code.

[OdedViner]

I will take it @rakeshgm @nirs