🚧 Fix issue where cert cleanup fails

- Delete temp directory using FileTree visitor recursively
- Update CertificateRequestBuilder to accept subject info directly from
  builder

src/main/java/de/mlessmann/certassist/DeleteRecursiveFileVisitor.java

@@ -0,0 +1,47 @@
+package de.mlessmann.certassist;
+
+import org.slf4j.Logger;
+import org.springframework.lang.NonNull;
+
+import java.io.IOException;
+import java.nio.file.FileVisitResult;
+import java.nio.file.FileVisitor;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.attribute.BasicFileAttributes;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
+public class DeleteRecursiveFileVisitor implements FileVisitor<Path> {
+
+    private static final Logger LOGGER = getLogger(DeleteRecursiveFileVisitor.class);
+
+    @NonNull
+    @Override
+    public FileVisitResult preVisitDirectory(Path dir, @NonNull BasicFileAttributes attrs) throws IOException {
+        return FileVisitResult.CONTINUE;
+    }
+
+    @NonNull
+    @Override
+    public FileVisitResult visitFile(Path file, @NonNull BasicFileAttributes attrs) throws IOException {
+        LOGGER.trace("Deleting file {}", file);
+        Files.delete(file);
+        return FileVisitResult.CONTINUE;
+    }
+
+    @NonNull
+    @Override
+    public FileVisitResult visitFileFailed(Path file, @NonNull IOException exc) throws IOException {
+        LOGGER.error("Could not delete file {}", file, exc);
+        throw exc;
+    }
+
+    @NonNull
+    @Override
+    public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
+        LOGGER.trace("Deleting directory {}", dir);
+        Files.delete(dir);
+        return FileVisitResult.CONTINUE;
+    }
+}