Formatting fixes to decorators utils module.
Added a `which` decorator to be used in functions which require a specific binary.
One less TODO. Check for the existence of the binary before running the function.
Don't obfuscate the`zip` built-in.
Mocked test for `salt.modules.archive.tar()`
Merge pull request #6349 from s0undt3ch/sprint/mock-salt.modules.archive

Mock tests for `salt.modules.archive`