Define a temporarily empty RulesDsl.makeRules method

When complete, this method will execute the DSL front-end, and return
the list of rules, if successful, otherwise report errors.

core/src/main/java/it/cavallium/warppi/math/rules/dsl/RulesDsl.java

@@ -0,0 +1,11 @@
+package it.cavallium.warppi.math.rules.dsl;
+
+import it.cavallium.warppi.math.rules.Rule;
+
+import java.util.List;
+
+public class RulesDsl {
+	public static List<Rule> makeRules(final String source) {
+		return null;
+	}
+}