Add sstorage p2p protocol -- part 1

[ping-ke]

doc about the sstorage p2p protocol, https://docs.google.com/document/d/1rfuGeCBU1Qj52gPOSyhefgb8hqLooTNPGiAeZbc85u4/edit Part 1 only contains the p2p protocol sstorage code and its dependencies.

• storage code (eth/protocols/sstorage):
  • handler: MakeProtocols and handle sstorage support message
  • peer: define sstorage peer and its request functions
  • protocol: define sstorage protocol
  • sync: contain the sync logic
• core/rawdb
  • read/write sstorage sync status to db
• sstorage
  • add read MaskKV
  • provide shard list support by the node

[cyl19970726]

I've written some code analysis that might help you when reviewing the code https://literate-wolfsbane-bf0.notion.site/p2p-network-code-review-6a6620b255be465988b2db5d6702a114

[qizhou]

What is the summary of the PR?

[blockchaindevsh]

Two points:

1. shard id list can be just communicated during handshake since it's not gonna change once started.
2. currently sstorage sync and precompile can be racing to update the same shard, there needs to be a lock to prevent a stale update.