x-callback-url delivers start position and video title, and back with resume position and duration

Feature requests on x-callback-url. The goal is to make vlc a shared app / component.

• Add more query parameters into x-callback-url from VLC:

• Initial playback start position in (milli)seconds.
• Video title to display.

• Add more result query parameters from VLC, append to the 'x-success=' url:

• Resume position in (milli)seconds (-1 or empty means video playback completed).
• Whole video duration in (milli)seconds.

Please refer to ​https://forum.videolan.org/viewtopic.php?f=36&t=124498