Make slash commands interface and load them dynamically

Slash commands are now loaded dynamically by implementing a SlashCommand interface and storing them in a loaded commands map.

src/main/java/wtf/beatrice/hidekobot/commands/slash/AvatarCommand.java

@@ -6,10 +6,17 @@ import net.dv8tion.jda.api.events.interaction.command.SlashCommandInteractionEve
 import net.dv8tion.jda.api.interactions.commands.OptionMapping;
 import org.jetbrains.annotations.NotNull;
 import wtf.beatrice.hidekobot.Cache;
+import wtf.beatrice.hidekobot.objects.SlashCommand;
 
-public class AvatarCommand
+public class AvatarCommand implements SlashCommand
 {
 
+    @Override
+    public String getCommandName() {
+        return "avatar";
+    }
+
+    @Override
     public void runSlashCommand(@NotNull SlashCommandInteractionEvent event)
     {
         // defer reply because this might take a moment