Enable gochecknoinits; fix lint issues; use consts for some vars

[alexandear]

This PR enables gochecknoinits linter. And fixes appeared issue by removing init() function from the cwe package.
Also, refactors InformationURI and DownloadURI initialization.

[codecov-commenter]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (4def3a4) 72.41% compared to head (35fa5ab) 72.38%.

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1022      +/-   ##
==========================================
- Coverage   72.41%   72.38%   -0.04%     
==========================================
  Files          50       50              
  Lines        3386     3382       -4     
==========================================
- Hits         2452     2448       -4     
  Misses        863      863              
  Partials       71       71              

Files	Coverage Δ
cwe/data.go	83.33% <100.00%> (-6.67%)	⬇️

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