[Commands] Cleanup #zone and #zoneinstance Commands. (#2202)

* [Commands] Cleanup #zone and #zoneinstance Commands.
- Cleanup messages and logic.
- Broke these commands out in to their own files.

* Update database.cpp

* Update database.cpp

* Update database.cpp

zone/gm_commands/zone_instance.cpp

@@ -0,0 +1,70 @@
+#include "../client.h"
+
+void command_zone_instance(Client *c, const Seperator *sep)
+{
+	int arguments = sep->argnum;
+	if (!arguments || !sep->IsNumber(1)) {
+		c->Message(Chat::White, "Usage: #zoneinstance [Instance ID] [X] [Y] [Z]");
+		return;
+	}
+
+	auto instance_id = std::stoul(sep->arg[1]);
+	if (!instance_id) {
+		c->Message(Chat::White, "You must enter a valid instance id.");
+		return;
+	}
+
+	if (!database.CheckInstanceExists(instance_id)) {
+		c->Message(
+			Chat::White,
+			fmt::format(
+				"Instance ID {} does not exist.",
+				instance_id
+			).c_str()
+		);
+		return;
+	}
+
+	auto zone_id = database.ZoneIDFromInstanceID(instance_id);
+	if (!zone_id) {
+		c->Message(
+			Chat::White,
+			fmt::format(
+				"Instance ID {} not found or zone is set to null.",
+				instance_id
+			).c_str()
+		);
+		return;
+	}
+
+	if (database.CharacterInInstanceGroup(instance_id, c->CharacterID())) {
+		c->Message(Chat::White, "You are already a part of this instance, sending you there.");
+		c->MoveZoneInstance(instance_id);
+		return;
+	}
+
+	if (!database.VerifyInstanceAlive(instance_id, c->CharacterID())) {
+		c->Message(
+			Chat::White,
+			fmt::format(
+				"Instance ID {} expired or you are not apart of this instance.",
+				instance_id
+			).c_str()
+		);
+		return;
+	}
+
+	auto x = sep->IsNumber(2) ? std::stof(sep->arg[2]) : 0.0f;
+	auto y = sep->IsNumber(3) ? std::stof(sep->arg[3]) : 0.0f;
+	auto z = sep->IsNumber(4) ? std::stof(sep->arg[4]) : 0.0f;
+
+	c->MovePC(
+		zone_id,
+		instance_id,
+		x,
+		y,
+		z,
+		0.0f,
+		sep->IsNumber(2) ? 0 : ZoneToSafeCoords
+	);
+}