Сreate a real "clean" `gulp` task to prepare theme for live deploy

[andriyun]

Сreate a real "clean" gulp task to prepare project theme for live deploy

Need to remove: .map,.scss files, remove unused library additions (only .min & required css should stay

[pabloguerino]

No need for this task anymore because of the way we are using docker and the assets gets cleaned up each time.
Libraries are taken from node_modules so no libraries should be on the project.
Removing source files seems a little overkill but doable if this is what we want.

[andypost]

We still need this task to switch from dev to prod & test locally. Also it require new tadk to clean scss file for prod deploy