## Description 

- simplify the network metrics such that only peak TPS is calculated per
epoch
- other data like realtime TPS can be done on the reading side, as the
view query takes < 100 ms to finish on a fully populated DB

this will
- shorten network metrics backfill from days to a couple of hours
- also on Explorer, metrics of current checkpoint and current TPS is
more realtime.

## Test Plan 

local run and verify

---
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### Type of Change (Check all that apply)

- [ ] protocol change
- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes