Add host cpu info

[ChrsMark]

This PR adds CPU information as proposed with #130.

The CPU related information go under the host.cpu namespace.

[ChrsMark]

Hey @mx-psi @frzifus !

I have moved the Frequency information out of this patch and only kept the resource attributes. I think we can unblock this one and add the Frequency as a metric later after we have #89 merged and #226 can give more clarity about metrics' namespace.
Let me know what you think :).

[frzifus]

LGTM, should we then add the frequency as a metric afterwards?

Missed (comment). 😄

[ChrsMark]

LGTM, should we then add the frequency as a metric afterwards?

Missed (comment). smile

:) Yeap I think we should treat it as a Metric. example:

➜  semantic-conventions git:(add_host_cpu_info) cat /proc/cpuinfo | grep MHz                                    
cpu MHz		: 3000.000
cpu MHz		: 1054.524
cpu MHz		: 1093.029
cpu MHz		: 3000.000
cpu MHz		: 3000.000
cpu MHz		: 3000.000
cpu MHz		: 3000.000
cpu MHz		: 3000.000
➜  semantic-conventions git:(add_host_cpu_info) cat /proc/cpuinfo | grep MHz
cpu MHz		: 1467.399
cpu MHz		: 3000.000
cpu MHz		: 3000.000
cpu MHz		: 3000.000
cpu MHz		: 3000.000
cpu MHz		: 3000.000
cpu MHz		: 2462.027
cpu MHz		: 3000.000

[mx-psi]

@AlexanderWert mind taking another look?

[joaopgrassi]

Please add a changelog entry

[joaopgrassi]

@ChrsMark make sure to resolve the discussions if you think they are resolved (if not then ask the persons if you can resolve). That would help others to see if this is in a final state or not.

[ChrsMark]

Thanks @joaopgrassi, based on the latest discussions/approvals all those are resolved. Marked them properly.

[ChrsMark]

@joaopgrassi @AlexanderWert anything else missing here?

[AlexanderWert]

@open-telemetry/specs-semconv-maintainers I think we are good to merge this

[joaopgrassi]

@open-telemetry/specs-semconv-approvers @open-telemetry/specs-semconv-maintainers we discussed this in the System semconv SIG and should be good to go. Will give it another day, but if nothing then I will merge.