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/objects/SlashCommand.java

@@ -0,0 +1,11 @@
+package wtf.beatrice.hidekobot.objects;
+
+import net.dv8tion.jda.api.events.interaction.command.SlashCommandInteractionEvent;
+import org.jetbrains.annotations.NotNull;
+
+public interface SlashCommand
+{
+    String getCommandName();
+    void runSlashCommand(@NotNull SlashCommandInteractionEvent event);
+
+}