[Feature]: Add LP fees to epoch summaries

[JonRay15]

Feature Overview

In order to allow users to make sense of their earnings on Vega
We will add summaries of LP fees earned to the end of epoch summaries
So that it is clear to users what they have earned

Tasks

A checklist of the tasks that are needed to develop the feature and meet the acceptance criteria and feature test scenarios.

• Add LP fees earned per epoch to all 3 APIs below

Additional Details (optional)

The current rewards APIs:

• /api/v2/rewards
• /api/v2/rewards/epoch/summaries
• /api/v2/rewards/summaries (Less important ... I have no idea if anyone uses this)

Currently contain per epoch summaries of:

• Rewards
  • Based on Taker fees paid
  • Based on Maker fees received
  • Based on LP fees received
  • Based on staking (aka "global rewards")
• Fees
  • Infra fees

It is unclear why this API stops at just the infra fees, when it could provide a per-epoch summary of the LP fees earned and once this was done this API would provide a holistic picture of all the rewards & fees that a party has earned per epoch.

We want to add these to it...

[gordsport]

Issue has been split leave LP fees in this one. Maker fees to be done under:

• Add MakerFees to FeeStats #9743