chore: prefer use of global TracerProvider/MeterProvider

[Flarna]

Remove setting of TracerProvider in samples where it is actually not needed as the global TracerProvider should be preferred on default.

I found it also inconsistent to set a TracerProvider but no MeterProvider.

Besides that I fixed some warnings in md files and net test on windows.

Refs.: open-telemetry/opentelemetry-js#2127

[codecov]

Codecov Report

Merging #450 (c1ec89f) into main (862ab4e) will decrease coverage by 0.01%.
The diff coverage is n/a.

❗ Current head c1ec89f differs from pull request most recent head a36fffe. Consider uploading reports for the commit a36fffe to get more accurate results

@@            Coverage Diff             @@
##             main     #450      +/-   ##
==========================================
- Coverage   95.22%   95.21%   -0.02%     
==========================================
  Files         133      133              
  Lines        8176     8178       +2     
  Branches      802      804       +2     
==========================================
+ Hits         7786     7787       +1     
- Misses        390      391       +1     

Impacted Files	Coverage Δ
...de/opentelemetry-instrumentation-net/test/utils.ts	96.15% <0.00%> (-3.85%)	⬇️

[obecny]

lgtm