Added forwarded header filter as bean

module-server/src/main/kotlin/de/twomartens/wahlrecht/configuration/FilterConfiguration.kt

@@ -0,0 +1,13 @@
+package de.twomartens.wahlrecht.configuration
+
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+import org.springframework.web.filter.ForwardedHeaderFilter
+
+@Configuration
+open class FilterConfiguration {
+  @Bean
+  open fun forwardedFilter(): ForwardedHeaderFilter {
+    return ForwardedHeaderFilter()
+  }
+}