Auto Walls T3

Settlements automatically build walls at tier 3. Defence buildings only for growing the garrison now.

Factions/Cultures affected:
– Humans
– Dwarfs
– High Elves
– Dark Elves
– Lizardmen
– Undead
– Skaven

Unaffected Factions/Cultures:
– Norscans
– Chaos
– Beastmen
– Wood Elves

Orcs:
Special case – Orcs still have to build walls with the Garrison building but moved the building from Tier 2 & 3 to Tier 1 & 2.