GitLab

- added images/ directory
- placing .svg images in images/
- moved default_N_percent directory to images/
- replaced the help_outline PNGs with SVG

Bug: 852872
Change-Id: I7c3083526a64304f461ed964b040767ba6d8afe4
Reviewed-on: https://chromium-review.googlesource.com/1210962Reviewed-by: Edward Jung <edwardjung@chromium.org>
Reviewed-by: Asanka Herath <asanka@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Dan H <harringtond@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589654}