See fee savings due to referree discount

[ckpringle]

Story

As a refereee I want to see my savings due to being in a referral set So that I can understand my savings

Acceptance Criteria

• [ ] I can see my current saving on trading fees over the past 30 epochs by asset

Tasks

• [ ] UX (if needed)
• [ ] Design (if needed)
• [ ] Team and stakeholder review
• [ ] Specs reviewed and created or adjusted
• [ ] Implementation
• [ ] Testing (unit and/or e2e)
• [ ] Code review
• [ ] QA review

Sketch

Would be some expansion of this

Additional Info

I am not sure Core finished this API ... and I doubt we will push very hard for it for now.

[JonRay15]

Not convinced we will ever do this