Headless: remove unused configuration options

This removes most unused configuration options in HeadlessBrowser::Options
and HeadlessBrowserContext::Options along with associated builders. Some
context options are kept for the sake of test coverage, because tests override
these options whereas production code overrides Browser options.

Change-Id: I8ec24b0df0a130a4b4db19939087d850ccb95262
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4143935
Reviewed-by: Peter Kvitek <kvitekp@chromium.org>
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1090424}