[Commands] Add #show special_abilities (#4043)

* [Commands] Add #show special_abilities

# Notes
- Allows operators to see what special abilities an NPC has.
- Move special ability values to `common/emu_constants.h`.
- Add `EQ::constants::GetSpecialAbilityMap()` and `EQ::constants::GetSpecialAbilityName()`.
- Add `NPC::DescribeSpecialAbilities(client)` to describe special abilities to a specified client.

# Images

* Update npc.cpp

zone/gm_commands/show/special_abilities.cpp

@@ -0,0 +1,13 @@
+#include "../../client.h"
+
+void ShowSpecialAbilities(Client* c, const Seperator* sep)
+{
+	if (!c->GetTarget() || !c->GetTarget()->IsNPC()) {
+		c->Message(Chat::White, "You must target an NPC to use this command.");
+		return;
+	}
+
+	NPC* t = c->GetTarget()->CastToNPC();
+
+	t->DescribeSpecialAbilities(c);
+}