Start implementing message-base commands

Slash commands can't be used for everything, so we need something to fall back on.

src/main/java/wtf/beatrice/hidekobot/objects/MessageCommand.java

@@ -0,0 +1,25 @@
+package wtf.beatrice.hidekobot.objects;
+
+import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
+
+public interface MessageCommand
+{
+
+    /**
+     * Get the command's label, which is used when determining if this is the correct command or not.
+     *
+     * @return the command label.
+     */
+    String getCommandName();
+
+    /**
+     * Run the command logic by parsing the event and replying accordingly.
+     *
+     * @param event the received message event. It should not be used for parsing message contents data as
+     *              the arguments already account for it in a better way.
+     * @param args a pre-formatted list of arguments, excluding the bot prefix and the command name.
+     *             This is useful because command logic won't have to change in case the bot prefix is changed,
+     *             removed, or we switch to another method of triggering commands (ping, trigger words, ...).
+     */
+    void runCommand(MessageReceivedEvent event, String[] args);
+}

src/main/java/wtf/beatrice/hidekobot/objects/SlashCommand.java

@@ -5,7 +5,18 @@ import org.jetbrains.annotations.NotNull;
 
 public interface SlashCommand
 {
+    /**
+     * Get the command's registered label, or how Discord sees and runs the registered command.
+     *
+     * @return the command label.
+     */
     String getCommandName();
+
+    /**
+     * Run the command logic by parsing the event and replying accordingly.
+     *
+     * @param event the received slash command event.
+     */
     void runSlashCommand(@NotNull SlashCommandInteractionEvent event);
 
 }