Add check_mode testing

[Tompage1994]

The role supports using check_mode. We should add some tests to ensure this is working properly and not being regressed like found in #815

              I agree this is a good change. I can see how we haven't spotted it before as well. I think we should add some check_mode testing to the tests to prove this out. If you fancy doing that, then great, otherwise I can raise an issue to fix that afterwards.

Originally posted by @Tompage1994 in #815 (review)

[w4hf]

Not sure if this is the right place to post this but I'm getting the error "msg": "check mode and async cannot be used on same task." when running in check mode.
Tested on ansible 2.15.0 with the role's role. Failed on task Managing Role Based Access Entries on Controller
Maybe we should have seperate check tasks ?