unify name and module on Attached property

- setting the attribute using the name of an attached module
- getting the attribute results in the module object

+ change names iodev to io, iodevClass to ioClass,
  sendRecv to communicate, HasIodev to HasIO

Change-Id: I200b63a5a7dc1453bf6ac998782b065645201900
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/27575
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

bin/secop-server

@@ -93,6 +93,7 @@ def main(argv=None):
     if args.relaxed:
         generalConfig.defaults['lazy_number_validation'] = True
         generalConfig.defaults['disable_value_range_check'] = True
+        generalConfig.defaults['legacy_hasiodev'] = True
     generalConfig.init(args.gencfg)
     logger.init(loglevel)