refactor(flyway): materialize clea-dbmigration as maven module

clea-dbmigration/pom.xml

+<?xml version="1.0" encoding="UTF-8" ?>
+<project
+  xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+>
+    <parent>
+        <artifactId>clea-server</artifactId>
+        <groupId>fr.gouv.clea</groupId>
+        <version>0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>clea-dbmigration</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.flywaydb</groupId>
+            <artifactId>flyway-core</artifactId>
+        </dependency>
+    </dependencies>
+
+</project>

pom.xml

@@ -30,6 +30,7 @@
     </description>
 
     <modules>
+        <module>clea-dbmigration</module>
         <module>clea-ws-rest</module>
         <module>clea-venue-consumer</module>
         <module>clea-batch</module>