Perf/parallel block downloader

[asdacap]

• Include Refactor/forward header provider #8254
• Currently forward sync only download from a single peer.
• This is a problem as the upload of a peer is more limited than download therefore the download speed really depends on the peer that the forward sync is being pinned to.
  • Depending on the peer, the download speed of the forward sync can be 0 (hang), 15 blk/s or 150 blks.
  • Since nethermind can consistently process at least 30blk/s a lot of the time when catching up, the node is waiting until it got lucky with a peer with fast upload.
  • This makes it hard to know if something is wrong with it or not.
  • Also makes performance benchmarking inconsistent as most of the time, it waiting for block download.
• This PR add the ability to dowload blocks and receipts in parallel.
• This provide a much more consistent forward sync download speed of around 200 block per sec.
• Works by having a map of hash->(block, receipts) that stores download requests.

Types of changes

What types of changes does your code introduce?

• Optimization

Testing

Requires testing

• Yes
• No

If yes, did you write tests?

• Yes
• No

Notes on testing