Fix Log Level Discrepancies

[akutz]

This patch fixes the way the log levels are handled upon creating a new libStorage client or server. The default level remains WARN (unless the environment variable LIBSTORAGE_DEBUG=true).

When LIBSTORAGE_DEBUG=true the log level is set to DEBUG and both HTTP request and response logging are enabled.

[codecov-io]

Codecov Report

Merging #521 into master will increase coverage by 0.11%.
The diff coverage is 57.14%.

@@            Coverage Diff            @@
##           master    #521      +/-   ##
=========================================
+ Coverage   27.99%   28.1%   +0.11%     
=========================================
  Files          33      33              
  Lines        1997    2010      +13     
=========================================
+ Hits          559     565       +6     
- Misses       1379    1384       +5     
- Partials       59      61       +2

Impacted Files	Coverage Δ
api/context/context_keys.go	65.38% <25%> (-10.13%)	⬇️
api/context/context.go	30.73% <76.92%> (+2.84%)	⬆️

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