Added an open/closing time to the material folder, as well as allow uploads depending on whether the teaching staff enables uploads for students to the folder.
Materials are accessible by students if staff uploaded it, or if it is their own upload.
Students can manage their own submissions.
Allow students to upload to folders to which they have write access to.
When uploading files, it is permissions of the parent folder that lets the user upload or not.
Authorise the material folder instead of materials in general when listing the folder.
Fix invalid property access when uploading new files.
Fix uploading by students.
Display the upload buttons for students if they have access to the given folder.
Specify the person who uploaded the file.