Add option to disable MFA

[matmair]

This PR adds a installation level option to disable MFA entirely. MFA is kept enabled by default but can be turned off via config.yaml or environment variable.

Replaces #7747
See #7746

[netlify]

✅ Deploy Preview for inventree-web-pui-preview canceled.

Name	Link
🔨 Latest commit	6cb02ca
🔍 Latest deploy log	https://app.netlify.com/sites/inventree-web-pui-preview/deploys/66a809400e4c3a00088ad923

[matmair]

@SchrodingersGat do we want to reflect the disabling of MFA in the UI? I see this as a very fringe use case - mostly for the demo site

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 3 lines in your changes missing coverage. Please review.

Project coverage is 83.52%. Comparing base (637a7fe) to head (6cb02ca).
Report is 326 commits behind head on master.

Files with missing lines	Patch %	Lines
src/backend/InvenTree/InvenTree/forms.py	50.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7757      +/-   ##
==========================================
- Coverage   83.52%   83.52%   -0.01%     
==========================================
  Files        1114     1114              
  Lines       49355    49364       +9     
  Branches     1571     1571              
==========================================
+ Hits        41225    41231       +6     
- Misses       7734     7737       +3     
  Partials      396      396              

Flag	Coverage Δ
backend	85.35% <66.66%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[SchrodingersGat]

Nice one @matmair thanks for implementing