[BATCH-503] Fix TX definition in samples. Also add multi-environment support in samples (mysql and derby as examples)

spring-batch-samples/src/main/sql/init.sql.vpp

@@ -16,7 +16,7 @@ CREATE TABLE TRADE  (
 	VERSION ${BIGINT},
 	ISIN VARCHAR(45) NOT NULL, 
 	QUANTITY ${BIGINT},
-	PRICE FLOAT, 
+	PRICE DOUBLE, 
 	CUSTOMER VARCHAR(45)
 );
  
@@ -24,7 +24,7 @@ CREATE TABLE CUSTOMER (
 	ID ${BIGINT} $!{IDENTITY} PRIMARY KEY $!{GENERATED},  
 	VERSION ${BIGINT},
 	NAME VARCHAR(45),
-	CREDIT FLOAT
+	CREDIT DOUBLE
 );
  
 INSERT INTO customer (id, version, name, credit) VALUES (1, 0, 'customer1', 100000);