Added Interface HasRequirement

src/de/banananetwork/dsa/requirements/HasRequirement.java

@@ -0,0 +1,13 @@
+package de.banananetwork.dsa.requirements;
+
+import java.util.Objects;
+
+public interface HasRequirement { //TODO Rename
+
+	Requirement getRequirement();
+
+	default boolean hasRequirement() {
+		return !Objects.isNull(getRequirement());
+	}
+
+}