remove response caching

Turn out, that caching on the client side does not play well when new
data is loaded into the system.

pdb-ui/src/main/java/org/lucares/pdbui/WebConfiguration.java

@@ -1,11 +1,9 @@
 package org.lucares.pdbui;
 
 import java.nio.file.Paths;
-import java.util.concurrent.TimeUnit;
 
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.http.CacheControl;
 import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
@@ -13,13 +11,9 @@ import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 public class WebConfiguration implements WebMvcConfigurer, HardcodedValues, PropertyKeys {
 
 	private final String outputDir;
-	private final int cacheDurationInSeconds;
 
-	public WebConfiguration(@Value("${" + PATH_GENERATED_IMAGES + "}") final String outputDir,
-			@Value("${" + CACHE_IMAGES_DURATION_SECONDS + ":" + CACHE_IMAGES_DURATION_SECONDS_DEFAULT
-					+ "}") final int cacheDurationInSeconds) {
+	public WebConfiguration(@Value("${" + PATH_GENERATED_IMAGES + "}") final String outputDir) {
 		this.outputDir = outputDir;
-		this.cacheDurationInSeconds = cacheDurationInSeconds;
 	}
 
 	@Override
@@ -28,7 +22,6 @@ public class WebConfiguration implements WebMvcConfigurer, HardcodedValues, Prop
 		final String pathPattern = "/" + WEB_IMAGE_OUTPUT_PATH + "/**";
 		final String resourceLocation = "file:" + Paths.get(outputDir).toAbsolutePath() + "/";
 
-		final CacheControl cacheControl = CacheControl.maxAge(cacheDurationInSeconds, TimeUnit.SECONDS);
-		registry.addResourceHandler(pathPattern).addResourceLocations(resourceLocation).setCacheControl(cacheControl);
+		registry.addResourceHandler(pathPattern).addResourceLocations(resourceLocation);
 	}
 }