Make ~/Templates work by simply placing files and folders there

Adds functionality so that placing any file in ~/Templates creates the same file in the context menu as a template. This also works for directories so you are able to create project skeletons. I think I accidentally made it so that if you already have a .desktop file in ~/.local/share/templates that points to ~/Templates, the .desktop file will take priority and there is no duplication.

This is my first time writing Qt code. Most of this is made by just copying neighboring code and best practices were not taken into account. Please pick at the code as much as possible.

Fixes BUG: 191632