feat: Caption services (608/708) metadata

[gkatsev]

Add an option for caption services metadata in case the user wants to specify labels for 608/708 captions, override the ones provided in the manifest, or needs to add more information like character encoding (this isn't currently available but will be added some time in the future).
For HLS, an EXT-X-MEDIA tag can be specified with an INSTREAM-ID attribute. We already support this. https://datatracker.ietf.org/doc/html/draft-pantos-hls-rfc8216bis-08#section-4.4.6.1
This PR updated mpd-parser which uses the ANSI 214 supplamental spec section 7.2 to parse out the same information from MPD files. videojs/mpd-parser#131.

Adds a property called captionServices which has properties of the caption service IDs like CC1 or SERVICE1 and allows a user to specify a language and label.

[codecov]

Codecov Report

Merging #1138 (22351a9) into main (44905d4) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1138      +/-   ##
==========================================
+ Coverage   86.44%   86.45%   +0.01%     
==========================================
  Files          39       39              
  Lines        9471     9489      +18     
  Branches     2183     2189       +6     
==========================================
+ Hits         8187     8204      +17     
- Misses       1284     1285       +1     

Impacted Files	Coverage Δ
src/media-groups.js	98.66% <100.00%> (-0.32%)	⬇️
src/util/text-tracks.js	89.62% <100.00%> (+1.32%)	⬆️

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