Add a background job to upload material archives

It creates the archive now. It doesn't yet upload it.

Contributes to issue CURA-8609.

cura/PrinterOutput/UploadMaterialsJob.py

@@ -0,0 +1,25 @@
+# Copyright (c) 2021 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from PyQt5.QtCore import QUrl
+import os  # To delete the archive when we're done.
+import tempfile  # To create an archive before we upload it.
+
+import cura.CuraApplication  # Imported like this to prevent circular imports.
+from UM.Job import Job
+
+
+class UploadMaterialsJob(Job):
+    """
+    Job that uploads a set of materials to the Digital Factory.
+    """
+
+    def run(self):
+        archive_file = tempfile.NamedTemporaryFile("wb", delete = False)
+        archive_file.close()
+
+        cura.CuraApplication.CuraApplication.getInstance().getMaterialManagementModel().exportAll(QUrl.fromLocalFile(archive_file.name))
+
+        print("Creating archive completed. Now we need to upload it.")  # TODO: Upload that file.
+
+        os.remove(archive_file.name)  # Clean up.