Make it an optional advancement of ogre

This used to be a custom unit in Legend of Wesmere, but it was removed at some point.

This commit makes Ogre advance to Great Ogre. It may instead be desirable to make this an optional advancement.

data/core/macros/optional_unit_advancements.cfg

@@ -86,3 +86,8 @@
     # Place in a campaign or scenario definition to allow Saurian Skirmisher to advance to Saurian Spearthrower.
     {ENABLE_ADVANCEMENT "Saurian Skirmisher" "Saurian Spearthrower" ()}
 #enddef
+
+#define ENABLE_GREAT_OGRE
+    # Place in a campaign or scenario definition to allow Ogre to advance to Great Ogre.
+    {ENABLE_ADVANCEMENT "Ogre" "Great Ogre" (set_experience=80)}
+#enddef

data/core/units/ogres/Great_Ogre.cfg

@@ -0,0 +1,84 @@
+#textdomain wesnoth-units
+
+[unit_type]
+    id=Great Ogre
+    name= _ "Great Ogre"
+    race=ogre
+    image="units/ogres/great-ogre.png"
+    hitpoints=76
+    movement_type=largefoot
+    [resistance]
+        arcane=80
+    [/resistance]
+    movement=5
+    profile="portraits/monsters/ogre.webp"
+    experience=150
+    level=3
+    alignment=neutral
+    advances_to=null
+    {AMLA_DEFAULT}
+    cost=43
+    usage=fighter
+    description= _ "Great Ogres are giant creatures that usually live alone in the wilderness, remarkably similar to humans in form, though large and misshapen. While they can be easily outrun or outsmarted, their strength is not to be underestimated."
+    die_sound={SOUND_LIST:OGRE_DIE}
+    [attack]
+        name=cleaver
+        description=_"cleaver"
+        type=blade
+        range=melee
+        damage=15
+        number=3
+    [/attack]
+
+    {DEFENSE_ANIM "units/ogres/great-ogre-defend.png" "units/ogres/great-ogre.png" {SOUND_LIST:OGRE_HIT} }
+
+    [attack_anim]
+        [filter_attack]
+            name="cleaver"
+        [/filter_attack]
+
+        [frame]
+            begin=-325
+            end=-250
+            image="units/ogres/great-ogre-attack-1.png"
+        [/frame]
+        [frame]
+            begin=-250
+            end=-150
+            image="units/ogres/great-ogre-attack-2.png"
+        [/frame]
+        [frame]
+            begin=-150
+            end=-75
+            image="units/ogres/great-ogre-attack-3.png"
+        [/frame]
+        [if]
+            hits=yes
+            [frame]
+                begin=-75
+                end=100
+                image=units/ogres/great-ogre-attack-2.png
+                sound=axe.ogg
+            [/frame]
+        [/if]
+        [else]
+            hits=no
+            [frame]
+                begin=-75
+                end=100
+                image=units/ogres/great-ogre-attack-2.png
+                sound={SOUND_LIST:MISS}
+            [/frame]
+        [/else]
+        [frame]
+            begin=100
+            end=200
+            image="units/ogres/great-ogre-attack-1.png"
+        [/frame]
+    [/attack_anim]
+    [idle_anim]
+        [frame]
+            image="units/ogres/great-ogre-idle-[1~3].png"
+        [/frame]
+    [/idle_anim]
+[/unit_type]