refactor/support multiple discord guilds with 1 nitrado server each + better handling for NitradoAPI

commands/gamertag-link.js

@@ -29,6 +29,14 @@ module.exports = {
     */
     run: async (client, interaction, args, { GuildDB }) => {
 
+      if (!client.exists(GuildDB.Nitrado) || !client.exists(GuildDB.Nitrado.ServerID) || !client.exists(GuildDB.Nitrado.UserID) || !client.exists(GuildDB.Nitrado.Auth)) {
+        const warnNitradoNotInitialized = new EmbedBuilder()
+          .setColor(client.config.Colors.Yellow)
+          .setDescription("**WARNING:** The DayZ Nitrado Server has not been configured for this guild yet. This command or feature is currently unavailable.");
+
+        return interaction.send({ embeds: [warnNitradoNotInitialized], flags: (1 << 6) });
+      }
+
       let playerStat = await client.dbo.collection("players").findOne({"gamertag": args[0].value});
       if (!client.exists(playerStat)) return interaction.send({ embeds: [new EmbedBuilder().setColor(client.config.Colors.Yellow).setDescription(`**Not Found** This gamertag \` ${args[0].value} \` cannot be found, the gamertag may be incorrect or this player has not logged onto the server before for at least \` 5 minutes \`.`)] });