Guardian Module Fixes

- eliminate duplicate internal IDs to make Guardian PD Size 4 and
  Guardian MRP 2E available
- fix Frontier ID ('edID') for all guardian modules
- fix prices for all guardian modules
- add missing Frontier internal names ('symbol')

modules/hardpoints/guardian_gauss_cannon.json

@@ -9,7 +9,7 @@
       "burstrof": 0.83,
       "class": 2,
       "clip": 1,
-      "cost": 0,
+      "cost": 543801,
       "damage": 70,
       "damagedist": {
         "T": 1
@@ -36,4 +36,4 @@
       }
     }
   ]
-}
+}