Add functionality for child bounties pallet

[rrtti]

Child bounties pallet (former sub-bounties extension) is here: paritytech/substrate#10309

This will most likely be proposed as part of a runtime on Kusama first, to be voted by the community before an audit is completed for Polkadot inclusion. Depending on timelines, it might be included in a runtime proposal in the near future - let's make sure to add any functionality we need on the bounties tab to be ready for the upgrade 🙏🏻

[emielsebastiaan]

👀

[xlc]

Now child bounty is live on Kusama, can we have this prioritized?

[h4x3rotab]

Yes. It would be nice to prioritize this feature