Reland "fwupd: Implement downloading firmware patch locally"

This is a reland of 211f9b341fbe8902d7b0d6029b8e2168a26cd992

Changes:
 - Adding the policy section of the annotator.
 - Add logging for "WriteFile" failures and change value for size
   param from 1 to 0.

Original change's description:
> fwupd: Implement downloading firmware patch locally
>
> Downloads a firmware patch from a Google-hosted server and stores it
> into the device's local tmp directory. The stored patch is applied to
> the peripheral with the matching device ID.
>
> Currently downloads from a hardcoded valid URI. Followup will allow
> downloading from dynamically fetched URI's.
>
> Bug: 1252981
> Test: ash_unittests

Change-Id: Iff1b6e488e1ab44fe1c67078f68b77675da6a090
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3355538
Reviewed-by: Nicolas Ouellet-Payeur <nicolaso@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Michael Checo <michaelcheco@google.com>
Cr-Commit-Position: refs/heads/main@{#956010}