Allow backspace in console

ampel-firmware/sensor_commands.cpp

@@ -92,10 +92,16 @@ namespace sensor_commands {
       break;
     case '\r': // discard carriage return
       break;
+    case '\b': // backspace
+      if (input_pos > 0) {
+        input_pos--;
+      }
+      break;
     default:
       // keep adding if not full ... allow for terminating null byte
-      if (input_pos < (MAX_COMMAND_SIZE - 1))
+      if (input_pos < (MAX_COMMAND_SIZE - 1)) {
         input_line[input_pos++] = input_byte;
+      }
       break;
     }
   }