feat: add CDI SE app entrypoint to run TaxCalculator with PT country

Author: otaviojava

cdi-api/src/main/java/com/otavio/jakarta/cdi/app/configuration/App.java

@@ -0,0 +1,12 @@
+package com.otavio.jakarta.cdi.app.configuration;
+
+public class App {
+
+    public static void main(String[] args) {
+        System.setProperty("app.country", "PT");
+        try (var container = jakarta.enterprise.inject.se.SeContainerInitializer.newInstance().initialize()) {
+            TaxCalculator taxCalculator = container.select(TaxCalculator.class).get();
+            System.out.println("Tax for 100: " + taxCalculator.calculate(new java.math.BigDecimal("100")));
+        }
+    }
+}