feat: allow disabling swagger ui and disable it by default

[fmartingr]

Adds a new variable to enable the Swagger UI SHIORI_HTTP_SERVE_SWAGGER.

Swagger UI is now disabled by default.

Closes #1025

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 34.71%. Comparing base (4aa0f51) to head (d84a169).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
internal/http/server.go	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1026      +/-   ##
==========================================
- Coverage   34.72%   34.71%   -0.02%     
==========================================
  Files          61       61              
  Lines        5324     5326       +2     
==========================================
  Hits         1849     1849              
- Misses       3251     3253       +2     
  Partials      224      224              

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