Add a templates: Intl::GetStringOptionTo<> to simplify the reading
of string from options.
Add GetCaseFirst and GetHourCycle into Intl for later reuse
by different Intl objects
Move some enum shared by Intl object into Intl::

Bug: v8:5751
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: If9ed1889a594f7c0ee6669b4679dda9169e4a771
Reviewed-on: https://chromium-review.googlesource.com/c/1297772Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57201}