Extend subtitles parser to recognize the format of automatically generated subtitles

[stanislaw]

The subtitles are parsed correctly when they are not auto-generated (and we already have a working unit test for this 🥳 ).

When they are auto-generated, the subtitles files contain more structure and lines with funny <c>...</c> tags that have to be recognized by the parser.

Here is an example:

WEBVTT
Kind: captions
Language: de

00:00:00.000 --> 00:00:02.869 align:start position:0%
 
hallo <00:00:00.430><c>ich </c><00:00:00.860><c>bin </c><00:00:01.290><c>david </c><00:00:01.720><c>gründer </c><00:00:02.150><c>der </c><00:00:02.580><c>lingus</c>

00:00:02.869 --> 00:00:02.879 align:start position:0%
hallo ich bin david gründer der lingus
 

00:00:02.879 --> 00:00:05.390 align:start position:0%
hallo ich bin david gründer der lingus
organic <00:00:03.336><c>und </c><00:00:03.793><c>erfinder </c><00:00:04.250><c>der </c><00:00:04.707><c>bilingue</c>

---

Seems directly relevant:

• https://gist.github.com/davidcortesortuno/64723e4262889f592def55c1927db651

[kamui-fin]

So far I got the parser to avoid including that additional markup in PR #31. We still need to write code to avoid duplicate lines, correct?

[kamui-fin]

Just added the duplicate removing code. Let me know if I can close this now