[E² Plugin] YouTube Plugin by Taapat

[kaptan57]

Youtube py3+git 1260
Youtube h1+git 1260

YENiLiKLER

Replaces slash with the underscore character in download file names
Previously, the slash character was removed, but it could corrupt file names

Thx @Taapat

[kaptan57]

Youtube py3+git 1261
Youtube h1+git 1261

YENiLiKLER

Use single quotes in the ffmpeg command for the downloaded files
Do not add backslash to special characters to avoid damaging the names.
See discussion in #271

Thx @Taapat

[kaptan57]

Youtube py3+git 1263
Youtube h1+git 1263

YENiLiKLER

Fix test on OpenAtv

Thx @Taapat

[kaptan57]

Youtube py3+git 1265
Youtube h1+git 1265

YENiLiKLER

Remove trailer video extraction
It seems to me that it doesn't work correctly, but I haven't found any examples to test.
Also update the try_get function in YouTubeVideoUrl

Thx @Taapat