Adopt to new loggin api

modules/joex/src/main/resources/reference.conf

@@ -18,6 +18,17 @@ docspell.joex {
     port = 7878
   }
 
+  # Configures logging
+  logging {
+    # The format for the log messages. Can be one of:
+    # Json, Logfmt, Fancy or Plain
+    format = "Json"
+
+    # The minimum level to log. From lowest to highest:
+    # Trace, Debug, Info, Warn, Error
+    minimumLevel = "Debug"
+  }
+
   # The database connection.
   #
   # It must be the same connection as the rest server is using.