Separate folder/file permission check as new lib #1760

Summary of the new feature / enhancement

The code in #1690 implements a folder permission check to see if it's considered secure. We should pull that out as a separate crate lib as I imagine it'll likely be reused in future resources for similar purpose.

Proposed technical implementation details (optional)

• Extend the API to validate both machine scope and user scope permissions
  • machine only allows administrators/root to have write permissions
  • user scope allows administrators/root to have write permissions in addition to the current security context
• Allow the API to validate files in addition to folders (or ideally a file check also implicitly checks the containing folder)