Remove abandoned campaigns.

(cherry picked from commit 07f8a203ea6366efe9746a773723810de13683d5)

resources/campaigns/Operation_Atilla.json

@@ -1,11 +0,0 @@
-{
-  "name": "Syria - Operation Atilla",
-  "theater": "Syria",
-  "authors": "Malakhit",
-  "recommended_player_faction": "Turkey 2005",
-  "recommended_enemy_faction": "Greece 2005",
-  "description": "<p>This is based on the Turkish invasion of Cyprus, and the Greek defense of the island. You must make sure to keep your beachhead at all costs, otherwise reclaiming it will be tricky. It is recommended to reduce the per-turn income rate for both factions in this scenario due to the large oil depots both sides have - setting it to around 15-20% is probably reasonable.</p>",
-  "version": "7.0",
-  "miz": "Operation_Atilla.miz",
-  "performance": 2
-}

resources/campaigns/Russian_Intervention_2015.json

@@ -1,11 +0,0 @@
-{
-  "name": "Syria - Russian Intervention 2015",
-  "theater": "Syria",
-  "authors": "Malakhit",
-  "recommended_player_faction": "Russia 2010",
-  "recommended_enemy_faction": "Insurgents (Hard)",
-  "description": "<p>This short campaign is loosely based on the 2015 Russian military intervention in Syria. It should be perfect for COIN operations, especially with the Hind. Not designed for campaign inversion.</p>",
-  "version": "7.0",
-  "miz": "Russian_Intervention_2015.miz",
-  "performance": 1
-}