[iOS] Move SettingsDetailItem to Legacy

This CL moves the existing SettingsDetailItem to Legacy and creates a
new SettingsDetailItem which is now a subclass of the TableViewItem.
The new SettingsDetailItem now support Dynamic Type.

Bug: 894791
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: Ia001bf2bdd59bb71a81d228ebf7f905f5600eebf
Reviewed-on: https://chromium-review.googlesource.com/c/1251625
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599943}
16 files changed