Rework on media module

[bmarty]

Content

Move code from the api module to the impl module and rearrange package organisation.
Also split code between multiple files.

Motivation and context

Improve build time and prepare work for media browser

Screenshots / GIFs

No change expected.

Tests

• No change expected

Tested devices

• Physical
• Emulator
• OS version(s):

Checklist

• Changes have been tested on an Android device or Android emulator with API 23
• 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
• Pull request includes a sign off
• You've made a self review of your PR

[bmarty]

Since the content is not the real content anymore, there is no need to have multiple identical previews.

[github-actions]

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[codecov]

Codecov Report

Attention: Patch coverage is 64.64286% with 99 lines in your changes missing coverage. Please review.

Project coverage is 83.06%. Comparing base (31f9fa2) to head (1b10aa4).
Report is 34 commits behind head on develop.

Files with missing lines	Patch %	Lines
...ies/mediaviewer/impl/local/video/MediaVideoView.kt	51.63%	54 Missing and 5 partials ⚠️
...s/mediaviewer/impl/DefaultMediaViewerEntryPoint.kt	0.00%	21 Missing ⚠️
...ediaviewer/impl/local/DefaultLocalMediaRenderer.kt	0.00%	9 Missing ⚠️
...libraries/mediaviewer/impl/local/LocalMediaView.kt	88.88%	1 Missing and 2 partials ⚠️
...aries/mediaviewer/impl/local/file/MediaFileView.kt	95.74%	0 Missing and 2 partials ⚠️
...braries/mediaviewer/impl/local/pdf/MediaPdfView.kt	81.81%	1 Missing and 1 partial ⚠️
.../impl/util/FileExtensionExtractorWithValidation.kt	60.00%	1 Missing and 1 partial ⚠️
...ies/mediaviewer/impl/local/image/MediaImageView.kt	94.44%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3967      +/-   ##
===========================================
+ Coverage    83.01%   83.06%   +0.05%     
===========================================
  Files         1795     1804       +9     
  Lines        45549    45587      +38     
  Branches      5370     5373       +3     
===========================================
+ Hits         37812    37869      +57     
+ Misses        5857     5832      -25     
- Partials      1880     1886       +6     

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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