Adding a campaign record and reworking scenario from header

Author: Morgan

mgz/header/scenario.py

@@ -27,11 +27,12 @@
     )),
     Padding(5),
     "elapsed_time"/Float32l,
-    "scenario_filename"/PascalString(lengthfield="scenario_filename_length"/Int16ul),
     If(lambda ctx: ctx._._.version == Version.DE, Struct(
+        # We should try a record with a determined starting time to see if those byte are before elapsed_time or not
         Padding(64),
         # If(lambda ctx: find_save_version(ctx) >= 13.34, Padding(64)) 4*16 = 64
     ))
+    "scenario_filename"/PascalString(lengthfield="scenario_filename_length"/Int16ul),    
 )
 
 # Scenarios have intro text, a bitmap, and cinematics.