Moved 3mf writer here from Uranium

CURA-1263

plugins/3MFWriter/ThreeMFWorkspaceWriter.py

@@ -0,0 +1,49 @@
+from UM.Workspace.WorkspaceWriter import WorkspaceWriter
+from UM.Application import Application
+from UM.Preferences import Preferences
+import zipfile
+from io import StringIO
+
+
+class ThreeMFWorkspaceWriter(WorkspaceWriter):
+    def __init__(self):
+        super().__init__()
+
+    def write(self, stream, nodes, mode=WorkspaceWriter.OutputMode.BinaryMode):
+        mesh_writer = Application.getInstance().getMeshFileHandler().getWriter("3MFWriter")
+
+        if not mesh_writer:  # We need to have the 3mf mesh writer, otherwise we can't save the entire workspace
+            return False
+
+        # Indicate that the 3mf mesh writer should not close the archive just yet (we still need to add stuff to it).
+        mesh_writer.setStoreArchive(True)
+        mesh_writer.write(stream, nodes, mode)
+        archive = mesh_writer.getArchive()
+
+        # Add global container stack data to the archive.
+        global_container_stack = Application.getInstance().getGlobalContainerStack()
+        global_stack_file = zipfile.ZipInfo("Cura/%s.stack.cfg" % global_container_stack.getId())
+        global_stack_file.compress_type = zipfile.ZIP_DEFLATED
+        archive.writestr(global_stack_file, global_container_stack.serialize())
+
+        # Write user changes to the archive.
+        global_user_instance_container = global_container_stack.getTop()
+        global_user_instance_file = zipfile.ZipInfo("Cura/%s.inst.cfg" % global_user_instance_container.getId())
+        global_user_instance_container.compress_type = zipfile.ZIP_DEFLATED
+        archive.writestr(global_user_instance_file, global_user_instance_container.serialize())
+
+        # Write quality changes to the archive.
+        global_quality_changes = global_container_stack.findContainer({"type": "quality_changes"})
+        global_quality_changes_file = zipfile.ZipInfo("Cura/%s.inst.cfg" % global_quality_changes.getId())
+        global_quality_changes.compress_type = zipfile.ZIP_DEFLATED
+        archive.writestr(global_quality_changes_file, global_quality_changes.serialize())
+
+        # Write preferences to archive
+        preferences_file = zipfile.ZipInfo("Cura/preferences.cfg")
+        preferences_string = StringIO()
+        Preferences.getInstance().writeToFile(preferences_string)
+        archive.writestr(preferences_file, preferences_string.getvalue())
+        # Close the archive & reset states.
+        archive.close()
+        mesh_writer.setStoreArchive(False)
+        return True