Reland "OnionSoup: Move web_bluetooth.mojom to public/mojom/bluetooth"

This is a reland of d5b00821af44d875d6cad42ae578b999ddf9316c

It updates //BUILD.gn and //content/public/common/BUILD.gn
in addition to the previous change to fix the dependency
problem.

Original change's description:
> OnionSoup: Move web_bluetooth.mojom to public/mojom/bluetooth
>
> This CL moves bluetooth folder from public/platform/modules to
> public/mojom/ to gather mojom files to mojom folder with
> creating web_bluetooth_mojo_bindings.
>
> Bug: 919393
> Change-Id: I42037e1c9738b03969e927dd00f6b24c2873b364
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1530369
> Reviewed-by: Kentaro Hara <haraken@chromium.org>
> Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
> Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
> Reviewed-by: John Budorick <jbudorick@chromium.org>
> Reviewed-by: Doug Turner <dougt@chromium.org>
> Reviewed-by: Colin Blundell <blundell@chromium.org>
> Commit-Queue: Julie Jeongeun Kim <jkim@igalia.com>
> Cr-Commit-Position: refs/heads/master@{#649061}

Bug: 919393
Change-Id: I61de3e625205e54959ad8d36c84eefa95f861035
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1559368
Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Julie Jeongeun Kim <jkim@igalia.com>
Cr-Commit-Position: refs/heads/master@{#652487}
40 files changed