Provide move file function in Project Data tab

[tdudgeon]

Now that we have the ability to create directories in the Project Data tab, the next thing the user will want to do is to move files into it using drag and drop.
Will first need API support.

[alanbchristie]

Suggest the following: -

• /file/move endpoint to move unmanaged files (to a new path)
• /path/move endpoint to move paths

I worry that any path that contains a ProjectFile/Managed File (an instance of a Dataset in a project) will cause all sorts of problems in the backend. So I think moving and deleting paths that contain ProjectFile instances will need to result in one of two actions: -

• Update the corresponding ProjectFile records to reflect the new path
• Prevent the move/removal