Unbonding watcher RegisterSpendNtfn performance

[Lazar955]

RegisterSpendNtfn for old delegations with low height will cause a scan up to the tip, this could be a performance bottleneck

[KonradStaniec]

Task should accomplish following goals:

• measure what is current latency for reporting unbonding transaction for staking transaction deep in the chain and which was already unbonded when reported. Example case:

1. Staker sends staking transaction at BTC height 10.
2. Staker unbonds it at height 5000
3. Staker reports staking transaction to Babylon alongside the inclusion proof when BTC height is 10000
4. Staker start earning rewards after receiving quorum in Covenant signatures.

Reporting Latency is measured from the moment staking transaction is reported to Babylon till reported reports corresponding unbonding transactions.

Measurements should be made in scenario of the considerable load i.e 30k staking transactions, spread out along 30k blocks, 20% of them is already unbonded.

The lower latency the better, as during the period after activating delegation, staker earns rewards without valid staking transaction.

• establish whether measured latency is acceptable.

Tentative values:
Ideally unbonding would be reported within 10-15 min time (1 BTC block)
Acceptable is anything lower thatn 1h (6 BTC blocks)

• If the current latency proves to be to high apply necessary improvements to the Vigliante reporter