Additional system info

[pearce8]

Additional read-only data here (our systems only): /etc/node_info.json

• Do we have what we need? @nhanford
• Tractable updates: schema? @nhanford @IanLee1521
• Adding this to Caliper metadata @dyokelson

[IanLee1521]

@pearce8 / anyone -- is there a good place you think that the schema should be documented? At the moment I'm considering either https://github.com/llnl/cmvl or https://github.com/LLNL/toss-configs which each have pros and cons. But certainly could be elsewhere too.

[nhanford]

I think either is fine--whichever makes sense for the best maintainability. Thanks for doing this!