refactor(sdk): separate default monitoring impl

[bojiang]

No description provided.

[codecov]

Codecov Report

Merging #3189 (048735a) into main (0e8b7b8) will decrease coverage by 0.20%.
The diff coverage is 13.82%.

@@            Coverage Diff             @@
##             main    #3189      +/-   ##
==========================================
- Coverage   21.69%   21.48%   -0.21%     
==========================================
  Files         101      102       +1     
  Lines        9735     9764      +29     
  Branches     1691     1698       +7     
==========================================
- Hits         2112     2098      -14     
- Misses       7575     7619      +44     
+ Partials       48       47       -1     

Impacted Files	Coverage Δ
src/bentoml/_internal/monitoring/default.py	0.00% <0.00%> (ø)
src/bentoml/_internal/server/http_app.py	0.00% <0.00%> (ø)
src/bentoml/_internal/monitoring/api.py	38.52% <25.00%> (-2.02%)	⬇️
src/bentoml/_internal/bento/build_config.py	33.69% <0.00%> (-0.38%)	⬇️
...bentoml/_internal/service/openapi/specification.py	90.56% <0.00%> (-0.05%)	⬇️
...c/bentoml/_internal/bento/build_dev_bentoml_whl.py	31.42% <0.00%> (+2.48%)	⬆️