Use more prominent log line to indicate start of processing

Issue: #530

modules/joex/src/main/scala/docspell/joex/process/ItemHandler.scala

@@ -35,6 +35,7 @@ object ItemHandler {
       analyser: TextAnalyser[F],
       regexNer: RegexNerFile[F]
   ): Task[F, Args, Unit] =
+    logBeginning.flatMap(_ =>
       DuplicateCheck[F]
         .flatMap(args =>
           if (args.files.isEmpty) logNoFiles
@@ -47,6 +48,7 @@ object ItemHandler {
               .map(_ => ())
           }
         )
+    )
 
   def itemStateTask[F[_]: Sync, A](
       state: ItemState
@@ -131,11 +133,16 @@ object ItemHandler {
     )
 
   private def logWarn[F[_]](msg: => String): Task[F, Args, Unit] =
-    Task(_.logger.warn(msg))
+    Task.log(_.warn(msg))
 
   private def logNoFiles[F[_]]: Task[F, Args, Unit] =
     logWarn(
       "No files to process! Either no files were given or duplicate check removed all."
     )
 
+  private def logBeginning[F[_]]: Task[F, Args, Unit] =
+    Task { ctx =>
+      val files = ctx.args.files.flatMap(_.name).mkString(", ")
+      ctx.logger.info(s"============ Start processing $files ============")
+    }
 }