Add base::Feature for encrypted archive deep scanning

Bug: 1466284
Change-Id: I97fd9060b716532b46e291e7256c1622ab04639f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4785890


Reviewed-by: Luc Nguyen <lucnguyen@google.com>
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Reviewed-by: Xinghui Lu <xinghuilu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1184817}