config: Parse model from JSON

[carrbs]

resolves #4412

Implements parsing of a JSON configuration file into an OpenTelemetryConfiguration, and tests it.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (3cecdcf) 81.1% compared to head (d6381c7) 81.2%. Report is 20 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #4806   +/-   ##
=====================================
  Coverage   81.1%   81.2%           
=====================================
  Files        150     150           
  Lines      10753   10759    +6     
=====================================
+ Hits        8725    8740   +15     
+ Misses      1872    1861   -11     
- Partials     156     158    +2     

Files	Coverage Δ
config/config.go	100.0% <100.0%> (ø)

... and 1 file with indirect coverage changes

[pellared]

Now, I see that the specification currently only requires implementing parsing of YAML: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/configuration/file-configuration.md#parse

@codeboten should we change to draft (or even close) this PR? WDYT?

[codeboten]

@pellared it might make sense to only implement YAML and leave JSON until there's a need for it. @carrbs do you have a specific need for JSON parsing to be implemented?

[carrbs]

@carrbs do you have a specific need for JSON parsing to be implemented?

@codeboten, not at all, I was just looking for low hanging fruit to work on. Closing this sounds good to me!