This commit introduces mp.utils.file_info() for querying information
on file paths, implemented for both Lua and Javascript.
The function takes a file path as an argument and returns a Lua table /
JS object upon success. The table/object will contain the values:
mode, size, atime, mtime, ctime and the convenience booleans is_file, is_dir.
On error, the Lua side will return `nil, error` and the Javascript side
will return `undefined` (and mark the last error).
This feature utilizes the already existing cross-platform `mp_stat()`
function.
TSaaristo
522bfe5be1