SRT subtitles folder for A11yIG

Auto load order:
1) <nodeId>.srt
2) default.srt

Encoding:
- UTF-8 with BOM/without BOM
- UTF-16 LE/BE with BOM

Example:
1
00:00:01,200 --> 00:00:03,500
第一句字幕

2
00:00:04,000 --> 00:00:06,000
第二句字幕
