Add support for run.shell task

[mcruzdev]

Many thanks for submitting your Pull Request ❤️!

What this PR does / why we need it:

Implement for RunTask.shell task.

Closes #246

Special notes for reviewers:

In progress, I will add some commits yet.

Additional information (if needed):

[mcruzdev]

Working on it.

[mcruzdev]

Hi @ricardozanini, @spolti and @mrsimonemms I think we need to change the FromYAMLSource from parser.go.

The yaml ("sigs.k8s.io/yaml") do the following:

1. Converts the []byte to interface{}
2. Converts the YAML to JSON ...

In the step 1 we are losing the order of Arguments that is crucial for the RUn.shell task. Could I change it to keep the order of Arguments?

[mrsimonemms]

@mcruzdev I actually stopped using FromYAMLSource recently, although for different reasons. I didn't like that the FromJSONSource method enforced the validation without giving me a way of controlling it - I wanted to allow the option of no validation and then have post-load hooks to allow for sensible defaults to be put in the schema if they weren't included.

[ricardozanini]

@mcruzdev feel free to use a compromise for this specific scenario.

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.