add custom fact listing all runners and properties

In the hiera's datafile we can find the registration tokens, used during the registration process.

But during the registration process, with a same registration tokens used several times, several runner token are generated. From the hiera's datafile point of view, the runner token is unknown. The custom fact should list following items for each runner configured on node :

• runner-token
• executor
• url (of coordinator)
• description (aka name).

It sound good to check the code if each time token is used, the type of the token is given. IE never user token alone but prefer registration-token or runner-token.