Added main class, made the game runnable again

src/main/java/eu/oschl/schmorn/Main.java

@@ -0,0 +1,15 @@
+package eu.oschl.schmorn;
+import eu.oschl.cli.Session;
+
+/**
+ * This class serves as the entry point for the game.
+ *
+ * @author Ondřej Schlaichert
+ */
+class Main {
+    static void main() {
+        var game = Setup.createGame();
+        var session = new Session(game);
+        session.start();
+    }
+}