NR S2: improve balancing

[ci skip]

(cherry-picked from commit 682a84ffec)

data/campaigns/Northern_Rebirth/scenarios/02_01_Infested_Caves.cfg

@@ -108,6 +108,8 @@
 
         [ai]
             recruitment_pattern=fighter,fighter,fighter,mixed fighter
+            grouping=defensive
+            support_villages=yes
         [/ai]
 
         {NOTRAIT_UNIT () "Dwarvish Stalwart" 31 28} {GUARDIAN} {NO_UPKEEP}
@@ -137,6 +139,7 @@
         controller=ai
         recruit=Troll Whelp,Troll,Troll Rocklobber
         {GOLD 300 400 500}
+        {INCOME 10 10 10}
         team_name=trolls
         user_team_name= _ "Trolls"
 
@@ -144,6 +147,18 @@
         id=Thung
         name= _ "Thung"
         canrecruit=yes
+
+        # try to increase surviving chances of side 5
+        [ai]
+            leader_value=1
+            [avoid]
+                x=25-40
+                y=19-21
+            [/avoid]
+        [/ai]
+
+        {NOTRAIT_UNIT () "Troll Rocklobber" 39 5} {GUARDIAN} {NO_UPKEEP}
+        {NOTRAIT_UNIT () "Troll Rocklobber" 39 11} {GUARDIAN} {NO_UPKEEP}
     [/side]
 
     [side]
@@ -703,7 +718,73 @@
         [/message]
     [/event]
 
-    # Meeting the dwarves, set new objectives
+    # When the eastern trolls are defeated the undead wii get their villages (not much)
+    # and focus on the player and the dwarves. The player is probably otherwise busy.
+    [event]
+        name=die
+        [filter]
+            side=4
+            canrecruit=yes
+        [/filter]
+        [filter_second]
+            race=undead
+        [filter_second]
+        [gold]
+            side=4
+            amount=50
+        [/gold]
+        [modify_side]
+            [filter_side]
+                side=4
+            [/filter_side]
+            income=12
+        [/modify_side]
+        [allow_recruit]
+            side=4
+            type=Dwarvish Steelclad
+        [/allow_recruit]
+        [disallow_recruit]
+            side=4
+            type=Dwarvish Thunderer
+        [/disallow_recruit]
+    [/event]
+
+    # Give gold to the allies in case their area is invaded
+    [event]
+        name=moveto
+        [filter]
+            side=2,3,5,6,7,8
+            x=24-31
+            y=21-25
+        [/filter]
+
+        [gold]
+            side=4
+            amount=130
+        [/gold]
+        [modify_side]
+            [filter_side]
+                side=4
+            [/filter_side]
+            income=12
+        [/modify_side]
+    [/event]
+
+    # This unit should only defend this location and not join the counterattack
+    [event]
+        name=side 4 turn refresh
+        first_time_only=no
+        [modify_unit]
+            [filter]
+                side=4
+                x=31
+                y=28
+            [/filter]
+            moves=0
+        [/modify_unit]
+    [/event]
+
+    # Meeting the dwarves
     [event]
         name=sighted
         [filter]