WL-3213 Move disabling zip to a private method

We want to be able to use this logic in multiple places so let's make a new
private method.
WL-3213 Disable zip for dropbox root folders

Currently only done for the Resources tool. It does not work so the option
should not be available.
Merge pull request #27 from ox-it/WL-3213

WL-3213 Disable zip on dropbox root folder