API GET /system_summary nice-to-have's

[satkunas]

It would be nice to expose additional system information in /system_summary such as:

• number of cpus
• meminfo
• OS uname
• uptime

So that we can develop admin helpers that can make recommendations based on the system setup. One example that comes to mind is the pfperl_api_processes (from #4423) which we can make a recommendation - or a warning - based on the amount of memory available.

[cgx]

Some of those metrics can be obtained from netdata.

[satkunas]

@cgx I'd prefer these metrics were not dependent on netdata. If we hope to run PF on embedded devices they should be standalone.