feat(1765): remove useless keys from the output yml

[martinjirku]

What type of PR is this?

/kind feature

What this PR does / why we need it:

This PR transforms yaml output by removing map[string]interfaces{} with no keys, or the nil fields. This PR utilizes the current implementation of the yaml transformation process in the "kompose" (1) object -> (2) []byte (json) -> (3) interface{} -> (4) []byte (yaml). Between steps 3 and 4, there is a chance to clean the data structure by removing any empty fields.

Which issue(s) this PR fixes:

Fixes #1758

Special notes for your reviewer:

IMHO, The empty artifacts (such as strategy {} , resources: {},...) are present because we have e.g. in the DeploymentSpec.Strategy struct not the reference (a pointer) to the struct, since this change would be outside of the kompose scope and I am not sure if it is feasible, I've decided to fix it by removing all empty fields.

Is this correct approach I should proceed with, or should I open (or search if a ticket exists) in the k8s/kubernetes repo for change in the API app types?

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[martinjirku]

I did not update docker tests, I will update it in next commit

[AhmedGrati]

@martinjirku any updates on this?

[martinjirku]

@AhmedGrati I've got much at work before Christmas. Still working... I've updated cca 40 tests sofar.

[cdrage]

AMAZING work! Thank you so much 🎉 🎉 🎉 🎉 🎉 🎉 🎉 🎉 🎉 🎉 🎉 🎉 🎉

LGTM!

[cdrage]

/lgtm

[cdrage]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cdrage, martinjirku

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