Issue #2281111: Porting 'Entity is of bundle (entity_is_of_bundle)' cond...

...ition to 8.x

See: d.o issue #2281111 - https://drupal.org/node/2281111
This creates an EntityIsOfBundle condition and an associated test that checks a simulated node entity's type and bundle.
Constraints we can specify already, so it should be done now. Also, let's just add todo line for each todo item + start each sentence uppercase end end it with a trailing point.