feat(v2): function totals recording rules

[alsoba13]

Adding a stacktrace filter field in the recording rules.

This way, we can define filter for function names and extend it in the future.

Examples of use:

# total cpu per service
- metric_name: 'pyroscope_metric_cpu_total_nanoseconds'
  matchers: ['{__profile_type__="..."}']
  group_by: ['service_name']
# garbage collection total cpu usage per service
- metric_name: 'pyroscope_metric_ingester_cpu_gc_total_nanoseconds'
  matchers: ['{__profile_type__="..."}']
  group_by: ['service_name']
  stacktrace_filter:
    type: 'function_name'
    function_name: 'runtime.gcBgMarkWorker'
    metric_type: total

With this, we should be able to extend it easily to: self function names, and self/total reg_exp function names

[alsoba13]

Optional. In absence of it total dimension (current implementation) is used.

[simonswine]

Ideally that should take the optional argument

Suggested change

	StacktraceFilter stacktrace_filter = 7;
	optional StacktraceFilter stacktrace_filter = 7;

[simonswine]

I guess changes you make here also need to be done to message RecordingRuleStore?

[alsoba13]

Yes, I need to make generate too. Will do it now

[simonswine]

Thanks for working on this. A few suggestions, let me know once you want me to take another look

[simonswine]

Rather than type I think it is nicer to use optional field per type and validate that only one is enabled at a time.

Alternatively there is also oneOf in protobuf: https://protobuf.dev/programming-guides/proto3/#using-oneof

Suggested change

	StacktraceFilterType type = 1;
	StacktraceFilterFunctionName function_name = 2;
	optional StacktraceFilterFunctionName function_name = 1;
	// And in the future
	// optional StacktraceFilterFunctionNameRegExp functionNameRegExp = 2;

[alsoba13]

Cool, I like this approach as well. I'll do it this way!

(I copied mine from Query)

[simonswine]

Careful in protobuf those field IDs should never change or be reused after deprecation, as that would break existing API users.

[simonswine]

Ideally that should take the optional argument

Suggested change

	StacktraceFilter stacktrace_filter = 7;
	optional StacktraceFilter stacktrace_filter = 7;

[simonswine]

I guess changes you make here also need to be done to message RecordingRuleStore?