Add JSON-RPC method: peersInfo

[leeyr338]

Add JSON-RPC method: peersInfo https://github.com/cryptape/cita/issues/280

• Add auto-generated files (from https://github.com/cryptape/cita-proto/commit/86f7e797c1137ad82a0ba41ca7c733ea247db37c)
• Modify license header: copyright from 2018 to 2019
• Other codes for peersInfo

[leeyr338]

Tips: If you review this PR, you can just review the following 3 commits:

• 316f2de
• 689fb83
• 9088deb And the other two commits are generated by script and protoc:
• c0c4be4