WebSubmit: improved DEMOPIC submission

• Fixed deletion of photos with Move_Photos_to_Storage.py
• Made Upload_Photos element optional (response element cannot be mandatory)
• In DEMOPIC SBI, moved "Report_Number_Generation" before "Make_Record"
• In DEMOPIC MBI, moved "Move_Photos_to_Storage" to step 2
• Display photos in the modification interface using the "default" icon (i.e. the first created one, which in principle would not be a large version)
• Log when submitted value cannot be read