Switch consumer to per-signal package

[dmathieu]

Description

This is a proposal showing the changes in the consumer package, as described in #10207.
With this change, the consumer package (and subpackages) can become stable, and new signals (such as profiles) can be added as new modules that aren't stable.

Testing

This is unit-tested.

[codecov]

Codecov Report

Attention: Patch coverage is 99.28826% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 92.54%. Comparing base (5ba6000) to head (246c770).

Files	Patch %	Lines
consumer/internal/consumertest/consumer.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10220      +/-   ##
==========================================
+ Coverage   92.53%   92.54%   +0.01%     
==========================================
  Files         387      397      +10     
  Lines       18191    18252      +61     
==========================================
+ Hits        16833    16892      +59     
- Misses       1019     1020       +1     
- Partials      339      340       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[bogdandrutu]

Feedback about implementation (does not mean I agree with the split decision):

1. clog - is a bad name since we may have to use something like this for component as well and may confuse between consumer vs component, maybe conslog?
2. Do we also need to split consumertest package? Do we need to rename it to be consistent to something like ctest (or constest)?
3. What about consumererror? Same question about naming.

[dmathieu]

I have renamed clog to conslog (did you want the same rename for ctrace and cmetric?)
I have also split consumertest and consumererror into per-signal packages, for their signal-specific things.