add ApplicationCommandDefinition prototype

lib/src/main/java/net/tomatentum/marinara/interaction/commands/ApplicationCommandDefinition.java

@@ -0,0 +1,20 @@
+package net.tomatentum.marinara.interaction.commands;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public record ApplicationCommandDefinition(
+    List<ExecutableCommandDefinition> executableDefinitons,
+    String applicationCommand
+) {
+
+    public ApplicationCommandDefinition(String applicationCommand) {
+        this(new ArrayList<>(), applicationCommand);
+    }
+
+    public ApplicationCommandDefinition addExecutableCommand(ExecutableCommandDefinition def) {
+        executableDefinitons.add(def);
+        return this;
+    }
+
+}