migrate: refactor examples to use the new FromFS function

migrate/example/cql/m1.cql

@@ -0,0 +1,15 @@
+-- Comment
+
+CREATE TABLE bar ( id int PRIMARY KEY);
+
+INSERT INTO bar (id) VALUES (1);
+
+-- CALL 1;
+
+INSERT INTO bar (id) VALUES (2);
+
+-- CALL 2;
+
+INSERT INTO bar (id) VALUES (3);
+
+-- CALL 3;