litep2p: Provide partial results to speedup GetRecord queries

[lexnv]

This PR provides the partial results of the GetRecord kademlia query.

This significantly improves the authority discovery records, from ~37 minutes to ~2/3 minutes.
In contrast, libp2p discovers authority records in around ~10 minutes.

The authority discovery was slow because litep2p provided the records only after the Kademlia query was completed. A normal Kademlia query completes in around 40 seconds to a few minutes.
In this PR, partial records are provided as soon as they are discovered from the network.

Testing Done

Started a node in Kusama with --validator and litep2p backend.
The node discovered 996/1000 authority records in ~ 1 minute 45 seconds.

Before & After

In this image, on the left side is libp2p, in the middle litep2p without this PR, on the right litep2p with this PR

Closes: #7077

cc @paritytech/networking

[dmitry-markin]

Release is needed.

[lexnv]

Yep, will do one soon, wanted to double-check first on our Kusama validator that this indeed solves the problem 🙏

[lexnv]

CPU

Litep2p without this PR was running before ~7:15 (spike—left side). On the right side is Litep2p with this PR.

The CPU consumption looks overall stable, with some fluctuations at ~10-minute intervals.
The peak CPU consumption has increased by ~6%, from 171% before to 182% current.

Considering the network's randomness and the ~18x speedup improvement in authority-discovery records, this small tradeoff (if any) appears justified.

Triage Report

The Some network error occurred when fetching erasure chunk warning appears in the first 2 minutes of starting the node. In contrast, before this PR the warning appeared for ~30 minutes.

Repo	Count	Level	Triage report
https://github.com/paritytech/polkadot-sdk/	437	warn_if_frequent	Some network error occurred when fetching erasure chunk
https://github.com/paritytech/polkadot-sdk/	25	warn	Recovery of available data failed.
https://github.com/paritytech/polkadot-sdk/	25	warn	Data unavailable for candidate .*
https://github.com/paritytech/polkadot-sdk/	12	warn	Report .: . to .. Reason: .. Banned, disconnecting. ( A collator provided a collation for the wrong para. Banned, disconnecting.)
https://github.com/paritytech/polkadot-sdk/	4	warn	fetch_pov_job
https://github.com/paritytech/polkadot-sdk/	3	warn	Importing locally an already known assignment
https://github.com/paritytech/polkadot-sdk/	1	warn	Report .: . to .. Reason: .. Banned, disconnecting. ( Same block request multiple times. Banned, disconnecting.)