## Description

Expose p2p functions for use in the sdk. 

These functions could also be copied over to the sdk. I dont have a preference of which is better.

use  `maxPeerBlockHeight` information to show the current network's best height.

Closes #3983
Relate to #3365

ref: the`highestBlock` in the response of `eth.isSyncing` call
https://web3js.readthedocs.io/en/v1.3.4/web3-eth.html#issyncing

Closes #3507

This PR make some tweaks to backfill after running e2e tests:
- Separates sync and backfill as two distinct processes that the node calls. The reason is because if sync fails then the node should fail but if backfill fails it is still possible to proceed.
- Removes peers who don't have the block at a height from the local peer list. As the process goes backwards if a node doesn't have a block at a height they're likely pruning blocks and thus they won't have any prior ones either. 
- Sleep when we've run out of peers, then try again.

state: move pruneBlocks function from consensus/state to state/execution

Closes #5414

Addresses a beginning component of #6255

Pass a set of private peer ids to the `PeerManager` and any node that exists in this set is not returned in the `Advertise` method.

closes: #6405

Co-authored-by: dongsam <dongsamb@gmail.com>
Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>
Co-authored-by: Aleksandr Bezobchuk <alexanderbez@users.noreply.github.com>

## Description

- Add `context.Context` to Privval interface

This pr does not introduce context into our custom privval connection protocol because this will be removed in the next release. When this pr is released.

Co-authored-by: Callum <cmwaters19@gmail.com>

This cleans up the `Router` code and adds a bunch of tests. These sorts of systems are a real pain to test, since they have a bunch of asynchronous goroutines living their own lives, so the test coverage is decent but not fantastic. Luckily we've been able to move all of the complex peer management and transport logic outside of the router, as synchronous components that are much easier to test, so the core router logic is fairly small and simple.

This also provides some initial test tooling in `p2p/p2ptest` that automatically sets up in-memory networks and channels for use in integration tests. It also includes channel-oriented test asserters in `p2p/p2ptest/require.go`, but these have primarily been written for router testing and should probably be adapted or extended for reactor testing.

This revises the new P2P `Transport` interface and does some preliminary code cleanups and simplifications.

The major change here is to add `Connection.Handshake()` for performing node handshakes (once the stream transport API is implemented, this can be done entirely independent of the transport).  This moves most of the handshaking logic into the `Router`, such as prevention of head-of-line blocking, validation of peer's `NodeInfo`, controlling timeouts, and so on. This significantly simplifies transports, completely removes the need for internal goroutines, and shares common logic across all transports. This also allows varying the handshake `NodeInfo` across peers, e.g. to vary `ListenAddr`. Similarly, connection filtering is also moved into the switch/router so that it can be shared between transports.

This improves the `peerStore` prototype by e.g.:

* Using a database with Protobuf for persistence, but also keeping full peer set in memory for performance.
* Simplifying the API, by taking/returning struct copies for safety, and removing errors for in-memory operations.
* Caching the ranked peer set, as a temporary solution until a better data structure is implemented.
* Adding `PeerManagerOptions.MaxPeers` and pruning the peer store (based on rank) when it's full.
* Rewriting `PeerAddress` to be independent of `url.URL`, normalizing it and tightening semantics.