input/file: export function OpenFileInputStream()
input/archive: export function OpenArchiveInputStream()
input/LocalOpen: new library for opening local files

Combines the "file" and the "archive" input plugins.
TagFile: use OpenLocalInputStream()
DecoderThread: use OpenLocalInputStream() for local files
input/Open: use OpenLocalInputStream()

Make the "open" method of plugins "file" and "archive" dummy methods
that always fail.  Instead, let InputStream::Open() hard-code access
to these two plugins by using OpenLocalInputStream().  This allows
simplifyin the algorithm for falling back to probing archive plugins.
archive/bzip2: use OpenLocalInputStream()
PlaylistStream: pass Path instance to playlist_open_path()

Convert filesystem charset to UTF-8 for playlist_list_open_uri().
This fixes one of many remaining charset bugs.
PlaylistStream: use OpenLocalInputStream()