[Feature] : Add local filesystem support

We need a way to access local filesystem.

Emscripten has a filesystem api that vlc already uses but it assumes the file that you open("/path/to/file", flag) is either:

• preloaded (in a .data file, thanks to the file packager in emcc)
• in an ArrayBuffer (with createDataFile) here is the wip commit

VLC does not only open media files, but also configuration files these can be handled with createDataFile.

Qt Example