This CL moves the timeline related methods of the
map model into timeline panel to encapsulate timeline
web component.

Bug: v8:10673, v8:10644

Change-Id: Ie82ca8dc920cb64bd5ba81ead1a346492bd2b738
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2302893Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Commit-Queue: Zeynep Cankara <zcankara@google.com>
Cr-Commit-Position: refs/heads/master@{#68908}