Add --stdout flag to CLI params

[abhinavbansal19961996]

Fixes #503

Types of changes

• Enhancement (project structure, spelling, grammar, formatting)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• My code follows the code style of this project. #
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

A description of the changes proposed in the Pull Request

This fixes this high priority issue: #503

1. I have introduced new flag --stdout in the ie command. When a user doesn't supply this flag, output won't be printed (Note that earlier it used to get printed in JSON format if no plugin is supplied or plug name is 'log') (Breaking change)
2. When --stdout flag is supplied, output will be printed in YAML format.

passed

[jmcook1186]

wow that was fast- thanks, we'll look over this in our internal PR triage call tomorrow.

[jmcook1186]

Thanks for this - requested some small changes

[narekhovhannisyan]

please import libs from the beginning of the file, and then newline, then other internal dependencies

[narekhovhannisyan]

the same here

[narekhovhannisyan]

same here

[abhinavbansal19961996]

@narekhovhannisyan @jmcook1186 Addressed. Pls re-review.

[narekhovhannisyan]

Hi @abhinavbansal19961996, I have executed the code locally, and everything looks fine! However, it's weird that if we are executing manifest without output and stdout flags, then it executes without any notification. So I'm pushing commit which will notify on console that none of stdout nor output flags are provided.

Requested changes where fixed.