Fix http response handling

[tjholm]

Fixes for response handling with headers and a synthetic setter for string/bytes responses for http.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[codecov-commenter]

Codecov Report

Merging #53 (adab42c) into develop (3b3e8b3) will increase coverage by 0.05%.
The diff coverage is 92.30%.

@@             Coverage Diff             @@
##           develop      #53      +/-   ##
===========================================
+ Coverage    95.98%   96.04%   +0.05%     
===========================================
  Files           13       13              
  Lines          748      759      +11     
===========================================
+ Hits           718      729      +11     
  Misses          30       30              

Impacted Files	Coverage Δ
nitric/faas.py	88.38% <92.30%> (+0.68%)	⬆️

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