As a user, I can use workflow validators to have better control over the testing artefacts

As a user, I can use workflow validators to have greater control over the transitions made on requirement, Test Plan and Test Execution issue types:

• all Tests related with this issue have been completed/finished
• all Tests related with this issue have passed (contributed to the OK coverage status)
• at least one Test related with this issue have failed (contributed to the NOK coverage status)