## Description
I'm just doing a self audit of the light client. There's a few things I've changed
- Validate trust level in `VerifyNonAdjacent` function
- Make errNoWitnesses public (it's something people running software on top of a light client should be able to parse)
- Remove `ChainID` check of witnesses on start up. We do this already when we compare the first header with witnesses
- Remove `ChainID()` from provider interface
Closes: #4538
## Description
Check block protocol version in header validate basic.
I tried searching for where we check the P2P protocol version but was unable to find it. When we check compatibility with a node we check we both have the same block protocol and are on the same network, but we do not check if we are on the same P2P protocol. It makes sense if there is a handshake change because we would not be able to establish a secure connection, but a p2p protocol version bump may be because of a p2p message change, which would go unnoticed until that message is sent over the wire. Is this purposeful?
Closes: #4790
## Description
This PR wraps the stdlib sync.(RW)Mutex & godeadlock.(RW)Mutex. This enables using go-deadlock via a build flag instead of using sed to replace sync with godeadlock in all files
Closes: #3242
Callum Waters
Marko
Erik Grinaker