[Commands] Consolidate #merchant_close_shop and #merchant_open_shop to #merchantshop (#3433)

* [Commands] Consolidate #merchant_close_shop and #merchant_open_shop to #merchantshop

# Notes
- `#merchant_close_shop` and `#merchant_open_shop` are now consolidated into `#merchantshop`.
- Command now works on any type of merchant instead of just regular merchants.
- Can be used on Merchants, Discord Merchants, Adventure Merchants, Norrath's Keepers Merchants, Dark Reign Merchants, and Alternate Currency Merchants.

* Update merchantshop.cpp

* Update merchantshop.cpp

* Update merchantshop.cpp

zone/gm_commands/merchantshop.cpp

@@ -0,0 +1,52 @@
+#include "../client.h"
+
+void command_merchantshop(Client *c, const Seperator *sep)
+{
+	const auto m = c->GetTarget();
+	if (
+		!m ||
+		!m->IsNPC() ||
+		(
+			m->GetClass() != MERCHANT &&
+			m->GetClass() != DISCORD_MERCHANT &&
+			m->GetClass() != ADVENTURE_MERCHANT &&
+			m->GetClass() != NORRATHS_KEEPERS_MERCHANT &&
+			m->GetClass() != DARK_REIGN_MERCHANT &&
+			m->GetClass() != ALT_CURRENCY_MERCHANT
+		)
+	) {
+		c->Message(Chat::White, "You must target a merchant.");
+		return;
+	}
+
+	const auto arguments = sep->argnum;
+	if (!arguments) {
+		c->Message(Chat::White, "#merchantshop close - Close your targeted merchant's shop");
+		c->Message(Chat::White, "#merchantshop open - Open your targeted merchant's shop");
+		return;
+	}
+
+	const bool is_close = !strcasecmp(sep->arg[1], "close");
+	const bool is_open  = !strcasecmp(sep->arg[1], "open");
+	if (!is_close && !is_open) {
+		c->Message(Chat::White, "#merchantshop close - Close your targeted merchant's shop");
+		c->Message(Chat::White, "#merchantshop open - Open your targeted merchant's shop");
+		return;
+	}
+
+	if (is_close) {
+		m->CastToNPC()->MerchantCloseShop();
+	} else if (is_open) {
+		m->CastToNPC()->MerchantOpenShop();
+	}
+
+	c->Message(
+		Chat::White,
+		fmt::format(
+			"{} shop for {}.",
+			is_close ? "Closed" : "Opened",
+			c->GetTargetDescription(m)
+		).c_str()
+	);
+}
+