Add mkvfontvalidator

[moi15moi]

Close #49

Breaking changes:

• Mkvpropedit.delete_fonts_of_mkv have been renamed Mkvpropedit.delete_all_fonts_of_mkv
• Mkvpropedit.path doesn't exist anymore. Now, use MKVUtils.MKVTOOLNIX_FOLDER to set the folder of mkvtoolnix.
• Mkvpropedit class have been renamed MKVPropedit.

[codecov-commenter]

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Codecov Report

❌ Patch coverage is 87.79343% with 26 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.10%. Comparing base (a226591) to head (ec656db).

Files with missing lines	Patch %	Lines
font_collector/mkvtoolnix/mkv_utils.py	67.24%	19 Missing ⚠️
font_collector/mkvtoolnix/mkvpropedit.py	95.23%	2 Missing ⚠️
font_collector/__init__.py	66.66%	1 Missing ⚠️
font_collector/mkvtoolnix/mkv_ass_file.py	90.00%	1 Missing ⚠️
font_collector/mkvtoolnix/mkv_font_file.py	88.88%	1 Missing ⚠️
font_collector/mkvtoolnix/mkvextract.py	97.77%	1 Missing ⚠️
font_collector/mkvtoolnix/mkvmerge.py	96.96%	1 Missing ⚠️
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Additional details and impacted files

@@            Coverage Diff             @@
##             main      #82      +/-   ##
==========================================
- Coverage   94.57%   94.10%   -0.47%     
==========================================
  Files          35       42       +7     
  Lines        1640     1798     +158     
==========================================
+ Hits         1551     1692     +141     
- Misses         89      106      +17     

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[moi15moi]

• VLC check if the attachment mime type is application/x-truetype-font or if the file extension is ttf, otf or ttc: https://code.videolan.org/videolan/vlc/-/blob/77b3f7cdeb61c7b0194ca029badafa4647b7d9fb/modules/codec/libass.c#L170-180
• MPV c is in this list or if the file extension is ttf, otf, ttc or otc: https://github.com/mpv-player/mpv/blob/c438732b239bf4e7f3d574f8fcc141f92366018a/sub/sd_ass.c#L149-L169
• The mastroska spec check if the attachment mime type is in this list:
  • application/x-truetype-font
  • application/x-font-ttf
  • application/vnd.ms-opentype
  • application/font-sfnt
  • application/font-woff (ignore because we don't support these)
  • font/ttf
  • font/otf
  • font/sfnt
  • font/woff (ignore because we don't support these)
  • font/collection

or if the attachment mime type is application/octet-stream and the file extension is ttf, otf, ttc or otc.

• MPC-HC only check the attachment mime type: https://github.com/clsid2/mpc-hc/blob/fb9f5dd48969d81e9ad9f80048258b0c4ad8094d/src/Subtitles/LibassContext.cpp#L841-L852

So in brief, no one does the same things.
I decided to respect the spec + to add application/x-font-otf which isn't in the spec, but will be one day