CRT BE integration - Dashboard

### Context

- https://github.com/Joystream/atlas/issues/3390

### Scope
- [ ] Integration with RPC node to fetch total revenue (revenue splits + direct sales)

Powering total revenue widget on the dashboard

<img width="461" alt="Screenshot 2023-09-11 at 18 11 50" src="https://github.com/Joystream/atlas/assets/93924525/dc1b2b09-6502-4011-b633-3a3da5ddedd2">
