As system, Xray must expose Test Plan related information to Xporter

The user should be able to export Test Plan issues using the Xporter template language.

In a Test Plan, it should be possible to:

• iterate though all Tests, and obtain the latest status
• iterate through all related Test Executions

In a Test it should be possible to iterate related Test Plans.
In a Test Execution it should be possible to export the "Test Plan" custom field.

It also should be possible to the access the "Test Plan" custom field of Test Executions.