Introduce module financer-common that hosts common code for server and (web) client

Also various fixes all over the place

financer-common/pom.xml

@@ -0,0 +1,36 @@
+<?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">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <artifactId>financer-parent</artifactId>
+        <groupId>de.77zzcx7.financer</groupId>
+        <version>11-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>financer-common</artifactId>
+    <packaging>jar</packaging>
+    <description>Common functionality of the financer app</description>
+    <name>financer-common</name>
+
+    <dependencies>
+        <dependency>
+            <groupId>javax.persistence</groupId>
+            <artifactId>javax.persistence-api</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <configuration>
+                    <skip>true</skip>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>