Implement efficient voting power rotation algorithm

[SebastianElvis]

No description provided.

[SebastianElvis]

https://github.com/babylonlabs-io/babylon-contract/blob/main/contracts/btc-finality/src/finality.rs#L567-L610

might already be the case, need double check

[maurolacy]

Yes, this is already there AFAIK. The TODOs there would be nice to have / required, btw:

• Online FPs verification.
• Filter out slashed / offline / jailed FPs.
• Purge old (height - finality depth) FP_SET entries to avoid bloating the storage.

Let's create issues for these.

[SebastianElvis]

Apart from the above 3, another thing we need here is to filter out FP without timestamped pub rand at the current height. So executing voting power rotation upon handling an IBC packet won't be enough