Adds a lot of empty classes with todos

Adds commands and permissions to plugin.yml
Uses the Spigot API instead of the Paper API
Reduces the Java version to 16, just in case.
Adds a lot of empty classes to show the intended plugin structure.

src/main/java/net/knarcraft/dropper/command/CreateArenaCommand.java

@@ -0,0 +1,17 @@
+package net.knarcraft.dropper.command;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+public class CreateArenaCommand implements CommandExecutor {
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender commandSender, @NotNull Command command, @NotNull String s,
+                             @NotNull String[] strings) {
+        //TODO: Implement command behavior
+        return false;
+    }
+
+}

src/main/java/net/knarcraft/dropper/command/EditArenaCommand.java

@@ -0,0 +1,17 @@
+package net.knarcraft.dropper.command;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+public class EditArenaCommand implements CommandExecutor {
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender commandSender, @NotNull Command command, @NotNull String s,
+                             @NotNull String[] strings) {
+        //TODO: Implement command behavior
+        return false;
+    }
+
+}

src/main/java/net/knarcraft/dropper/command/JoinArenaCommand.java

@@ -0,0 +1,18 @@
+package net.knarcraft.dropper.command;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+public class JoinArenaCommand implements CommandExecutor {
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender commandSender, @NotNull Command command, @NotNull String s,
+                             @NotNull String[] strings) {
+        //TODO: Implement command behavior
+        //TODO: Remember to check if the player is already in an arena first!
+        return false;
+    }
+
+}

src/main/java/net/knarcraft/dropper/command/LeaveArenaCommand.java

@@ -0,0 +1,18 @@
+package net.knarcraft.dropper.command;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+public class LeaveArenaCommand implements CommandExecutor {
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender commandSender, @NotNull Command command, @NotNull String s,
+                             @NotNull String[] strings) {
+        //TODO: Implement command behavior
+        //TODO: If the player isn't currently in an arena, just display an error message
+        return false;
+    }
+
+}

src/main/java/net/knarcraft/dropper/command/RemoveArenaCommand.java

@@ -0,0 +1,18 @@
+package net.knarcraft.dropper.command;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+public class RemoveArenaCommand implements CommandExecutor {
+
+    @Override
+    public boolean onCommand(@NotNull CommandSender commandSender, @NotNull Command command, @NotNull String s,
+                             @NotNull String[] strings) {
+        //TODO: Implement command behavior
+        //TODO: Make sure to kick players if the arena is currently in use
+        return false;
+    }
+
+}