refactor(installer/windows): move nsis code

[ReenigneArcher]

Description

Just moving NSIS packaging in preparation for LizardByte/roadmap#76, which is probably needed for #3905 (or #3369)

Screenshot

Issues Fixed or Closed

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 11.51%. Comparing base (883eff5) to head (4fd47e7).
⚠️ Report is 121 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3915   +/-   ##
=======================================
  Coverage   11.51%   11.51%           
=======================================
  Files          92       92           
  Lines       17499    17499           
  Branches     8152     8152           
=======================================
  Hits         2015     2015           
  Misses      12988    12988           
  Partials     2496     2496           

Flag	Coverage Δ
Linux	11.14% <ø> (ø)
Windows	12.99% <ø> (ø)

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[codecov]

Bundle Report

Bundle size has no change ✅