* Add mobile device deploy document (#624)

* add dygraph prune quick_start

* add mobile deploy doc

* complete deploy doc

* add images

* fix a error;

* fix some error
Co-authored-by: Ngmm <38800877+mmglove@users.noreply.github.com>

* fix prune_io
Co-authored-by: Ngmm <38800877+mmglove@users.noreply.github.com>