[Tab Resume 2.0] Connect handlers and ranking service

Connect handlers to visit_url_ranking_service and fetchers. Add flags to
control which handlers get added to the helper. Add config in case we
want to add more params to the fetchers.

Design Doc:
https://docs.google.com/document/d/1w7I9VzvY2orRdKNAydb60NaaEOdnMXtlc8XUsSH75SM/edit?pli=1

Bug: 335200723
Change-Id: I1188e45e4a9dc85494c3a1195eaa39372ceb2b8c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5745180
Reviewed-by: Roman Arora <romanarora@chromium.org>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Commit-Queue: Marlon Facey <mfacey@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1335836}