migration to JPA annotations

- added JPA annotations to POJO classes
- merged JPA Repos with Hibernate repos so we only use JPA
- renamed .txt files to .sql
- moved Spring configuration files so it is easier to use them inside
JUnit tests

src/main/resources/spring/applicationContext-dataSource.xml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+	Application context definition for PetClinic Datasource.
+-->
+<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		xmlns:p="http://www.springframework.org/schema/p"
+		xmlns:context="http://www.springframework.org/schema/context" 
+		xmlns:jdbc="http://www.springframework.org/schema/jdbc"
+		xsi:schemaLocation="
+			http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
+			http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
+			http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd">
+				
+	<!-- ========================= DATASOURCE DEFINITION ========================= -->				
+
+	<!-- Configurer that replaces ${...} placeholders with values from a properties file -->
+	<!-- (in this case, JDBC-related settings for the dataSource definition below) -->
+	<context:property-placeholder location="classpath:spring/jdbc.properties"/>
+
+	<!-- DataSource configuration for Apache Commons DBCP. -->
+	<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"
+			p:driverClassName="${jdbc.driverClassName}" p:url="${jdbc.url}"
+			p:username="${jdbc.username}" p:password="${jdbc.password}"/>
+	
+	<!-- JNDI DataSource for JEE environments -->
+	<!--
+	<jee:jndi-lookup id="dataSource" jndi-name="java:comp/env/jdbc/petclinic"/>
+	-->
+
+	<!-- Database initializer. If any of the script fails, the initialization stops. -->
+	<!-- As an alternative, for embedded databases see <jdbc:embedded-database/>. -->
+	<jdbc:initialize-database data-source="dataSource">
+		<jdbc:script location="${jdbc.initLocation}"/>
+		<jdbc:script location="${jdbc.dataLocation}"/>
+	</jdbc:initialize-database>
+
+</beans>