Add mana rewards statistics (Nova) [medium]

[begonaalvarezd]

Description

Priority: medium

We should provide statistics about the mana rewards generated per epoch. The network only knows about committed(past/ended) epochs, so probably rewards only make sense at an epoch level. Rewards statistics relate to account outputs and delegation outputs.

Afaik, this needs an INX endpoint

Motivation

Improve statistics to accomodate to new IOTA 2.0 features, like rewards

Requirements

Open questions (optional)

Are you planning to do it yourself in a pull request?

No.