Complete integrity check violations

thanks, PR looks good I just added a minor note / suggestion.

I've not seen any coverage for the following points though? -> Setting needs work.
* Check that required modules are enabled
* "The data type of the configured context does not match the context's %name requirement."

So maybe, get this merged and open a follow-op or complete it here?
Also I'm wondering, is this the complete list compiled from what Drupal 7 does? We should make sure we do not miss anything by checking d7 integrity checks, but it seems you have done so already? :)

I think we also miss integrity checks in data processors. Just added the following comment:

// Note that accessing an unavailable variable will throw an evaluation
// exception. That's exactly what needs to happen. Invalid tokens must
// be checked when checking integrity.
$rules_state->getVariable($variable_name);

Then, action & condition plugins must be able to complete an integrity check for their configuration also. Then, we need to implement this for the component integration such that we can check a used component exists and all required contexts are configured.