Remove the need to register slash commands separately

We modified the slash command interface to allow getting command data, and created a generic implementation of it that automatically retrieves data from the command data. The interface should not be used now. Instead, extending the implementation is preferred as it provides a semi-working command already.

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

@@ -1,14 +1,19 @@
 package wtf.beatrice.hidekobot.commands.slash;
 
 import net.dv8tion.jda.api.events.interaction.command.SlashCommandInteractionEvent;
+import net.dv8tion.jda.api.interactions.commands.build.CommandData;
+import net.dv8tion.jda.api.interactions.commands.build.Commands;
 import org.jetbrains.annotations.NotNull;
-import wtf.beatrice.hidekobot.objects.SlashCommand;
+import wtf.beatrice.hidekobot.objects.SlashCommandImpl;
 
-public class PingCommand implements SlashCommand
+public class PingCommand extends SlashCommandImpl
 {
     @Override
-    public String getCommandName() {
-        return "ping";
+    public CommandData getSlashCommandData()
+    {
+
+        return Commands.slash("ping",
+                "Test if the bot is responsive.");
     }
 
     @Override