orders: Scrape order date from SAP order view

This allows to assign a date to orders that do not go through a
requisition, for example some framework agreement orders.

orders.py

@@ -289,6 +289,9 @@ def scrape_order_ME23N(session, meta, num):
     session.findById('wnd[1]').sendVKey(0)
 
     content = session.findById('wnd[0]/usr')
+    date = parse_date(content.findByName('MEPO_TOPLINE-BEDAT', 'GuiCTextField').Text)
+    old = meta.setdefault('order-date', date)
+    assert old == date
 
     # Expand Header
     session.findById('wnd[0]').sendVKey(26) # Ctrl+F2