Moves all main files to main.*
Creates a separate directory for images and moves the icon there
Renames resources ID to match file names.

Bug: 1111229
Change-Id: Idbf49a3fb273bf7a4a64cb1431087db1199a9ed3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2409657
Commit-Queue: Bo Majewski <majewski@chromium.org>
Reviewed-by: Alex Danilo <adanilo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809630}