feat: add contract reference policy

[jjeroch]

Description

Adding ContractReference policy with attributes and all links

Why

Part of the new standard

Issue

#176

Checklist

• I have followed the contributing guidelines

Definition of Done

• New "contractReference" policy added to the system
• Right operand set to "{bilateralContractName}"
• Policy applicable for any useCase type
• Policy can get used for "Usage" types only
• Policy active as of today's date
• No regex or transactional attributes required

[evegufy]

why was main merged in this branch? it's going to the release branch and in the diff, I see loads of things not related to this change

[jjeroch]

why was main merged in this branch? it's going to the release branch and in the diff, I see loads of things not related to this change

Anwenderfehler. Schauen gerade ob wir das noch raus bekommen oder nen neuen PR benötigen

[Phil91]

why was main merged in this branch? it's going to the release branch and in the diff, I see loads of things not related to this change

I did rebase to the rc.2 branch.

@jjeroch fyi