Add implementation of otlploggrpc configuration

[XSAM]

part of #5056

Most of the codes are copied from otlploghttp.

I will try to make internal/conf as a shared go template file so otlploghttp can use a shared setting struct with otlploggrpc in the following PRs.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 93.10345% with 14 lines in your changes missing coverage. Please review.

Project coverage is 84.8%. Comparing base (5331939) to head (b6744d8).

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #5383     +/-   ##
=======================================
+ Coverage   84.5%   84.8%   +0.2%     
=======================================
  Files        269     269             
  Lines      17892   18077    +185     
=======================================
+ Hits       15132   15331    +199     
+ Misses      2440    2420     -20     
- Partials     320     326      +6     

Files	Coverage Δ
exporters/otlp/otlplog/otlploggrpc/config.go	93.4% <93.1%> (+93.4%)	:arrow_up:

... and 2 files with indirect coverage changes

[pellared]

I will try to make this as a shared go template file so otlploghttp can use a shared logic with otlploggrpc in the following PRs.

Keep in mind that I am not sure if this would be worth the effort given these configs are not 1:1.

[XSAM]

Two things I think we can make as a shared template in the following PRs:

• internal/conf
• TLS certificate methods