Unpublish PSDropbin Module from PowerShell Gallery

[MarkMichaelis]

Our PSDropbin module no longer works with current Dropbox API. Furthermore, the functionality is replaced by ExpanDrive. For this reason, we need to unpublish it (if that makes sense) and remove if from the items that are deployed during the PSToolbox build.

1. Research the right way to unpublish the module from PowerShell Gallery
2. Unpublish the module from PowerShell Gallery
3. Remove it from the PSToolbox build