chore(common): bumpe MSRV to 1.57

[TommyCpp]

• Bumpd MSRV to 1.57. The base64 bumped their MSRV to 1.57, which caused reqwest and other create to bump MSRV too. Since base64 is a widely used create I think we should bump it too.
• Fixed doc test in semconv.
• Added a unit test on jaeger remote sampler following Invalid expectations of JSON format for Jaeger remote sampling strategies opentelemetry-specification#3126

[codecov]

Codecov Report

Base: 69.3% // Head: 69.4% // Increases project coverage by +0.0% 🎉

Coverage data is based on head (29b5050) compared to base (0ef87ad).
Patch coverage: 54.5% of modified lines in pull request are covered.

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #953   +/-   ##
=====================================
  Coverage   69.3%   69.4%           
=====================================
  Files        116     116           
  Lines       9090    9103   +13     
=====================================
+ Hits        6308    6318   +10     
- Misses      2782    2785    +3     

Impacted Files	Coverage Δ
opentelemetry-api/src/lib.rs	100.0% <ø> (ø)
opentelemetry-jaeger/src/lib.rs	93.0% <ø> (ø)
opentelemetry-zipkin/src/lib.rs	100.0% <ø> (ø)
opentelemetry/src/lib.rs	100.0% <ø> (ø)
...try-sdk/src/trace/sampler/jaeger_remote/sampler.rs	21.4% <54.5%> (+21.4%)	⬆️
...etry-sdk/src/trace/sampler/jaeger_remote/remote.rs	18.1% <0.0%> (+18.1%)	⬆️

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