Dual licensing: AGPL + Element Commercial

[bmarty]

Content

This PR mimics what has been done on element-hq/element-x-ios#3657.

Could be review commit per commit, for the big commit, this is 2 replace all, so I guess it can just be ignored...

Motivation and context

Make it clear that the code is dual licensed.

Screenshots / GIFs

There should be no impact on any code.

Tests

• NA

Tested devices

• NA

Checklist

• Changes have been tested on an Android device or Android emulator with API 24
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• Pull request title will be used in the release note, it clearly define what will change for the user
• Pull request includes screenshots or videos if containing UI changes
• You've made a self review of your PR

[github-actions]

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[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 83.28%. Comparing base (a33266c) to head (2b9594e).
Report is 5 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #4118   +/-   ##
========================================
  Coverage    83.28%   83.28%           
========================================
  Files         1885     1885           
  Lines        49098    49098           
  Branches      5764     5764           
========================================
  Hits         40890    40890           
  Misses        6139     6139           
  Partials      2069     2069           

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[ganfra]

Thanks, LGTM!