Add the config source manager

[pjanotti]

A follow-up to #295 that superseded #277.

This brings the config source manager from the core repository that is not publicly exposed. The manager will be used to implement a provider that uses config sources to inject data in configuration. This code was originally reviewed on the collector core repository.

/cc @owais

[codecov]

Codecov Report

Merging #303 (4c3e37d) into main (689eebb) will increase coverage by 0.74%.
The diff coverage is 89.88%.

@@            Coverage Diff             @@
##             main     #303      +/-   ##
==========================================
+ Coverage   86.82%   87.57%   +0.74%     
==========================================
  Files          24       25       +1     
  Lines        1579     1915     +336     
==========================================
+ Hits         1371     1677     +306     
- Misses        173      194      +21     
- Partials       35       44       +9     

Impacted Files	Coverage Δ
internal/configprovider/manager.go	89.88% <89.88%> (ø)
internal/configprovider/helpers.go	36.36% <0.00%> (+36.36%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 689eebb...4c3e37d. Read the comment docs.

[tigrannajaryan]

I do not quite understand why are we not implementing the configsource support in Collector core. Why do we need the config manager here? I thought it can be internal in Collector core and still do its job. I am confused.

[pjanotti]

I do not quite understand why are we not implementing the configsource support in Collector core. Why do we need the config manager here? I thought it can be internal in Collector core and still do its job. I am confused.

It is a good question: internal is not visible on other repositories - so until that is moved outside internal we can't use it. The obvious risk is the code diverging, but, that is the point here per my understanding: we want to experiment before making it public on the core repository.

[tigrannajaryan]

LGTM. Discussed with @pjanotti that this is a temporary approach to speed up the delivery. We will eventually rely on the Manager in the core.