Add QR code generator to the URL bar

[bsclifton]

Test plan

1. Start Brave browser
2. Navigate to any website (e.g. brave.com)
3. Click inside the location bar
4. An action icon shows up in the location bar. When clicked a bubble with QR code shows up.

Description

QR code sharing disabled with #15008 in browser version 1.23

Security review for this feature was recently done and was approved:
https://github.com/brave/security/issues/450

No calls are being made to Google (or elsewhere) to generate the code OR for the URL generated (ex: it's not using a redirect link)

[stephendonner]

Verified PASSED using the inline testplan with build

Brave	1.26.24 Chromium: 91.0.4472.57 (Official Build) nightly (x86_64)
Revision	e3443317fa07f1e9997e4a9c738eddfefc3c0292-refs/branch-heads/4472_54@{#6}
OS	macOS Version 11.3.1 (Build 20E241)

Steps:

1. new profile, started Brave
2. loaded brave.com
3. clicked inside the location bar
4. clicked on the windows-looking QR code icon, to the left of the Brave Shield icon
5. confirmed that scanning the QR code loaded brave.com
6. confirmed that scanning the downloaded PNG of the QR code took me to brave.com
7. changed the prepopulated URL to https://www.mozilla.org/en-US/404, confirmed that the QR-code image updated
8. scanned the new QR code, both inline and downloaded, and confirmed it took me to the newly-inputted URL (https://www.mozilla.org/en-US/404)

example	example	brave.com QR code	example	mozilla.org/en-US/404 QR code

---

Verification PASSED on Win 10 x64 using the following build:

Brave | 1.27.24 Chromium: 91.0.4472.77 (Official Build) nightly (64-bit)
--- | ---
Revision | 1cecd5c8a856bc2a5adda436e7b84d8d21b339b6-refs/branch-heads/4472@{#1246}
OS | Windows 10 OS Version 2009 (Build 19042.1023)

• ensured that the QR code is being displayed within the URL bar when visiting brave.com
  • scanned it with an iOS device and ensured that the correct page is being loaded
  • ensured that you can download the QR image and use it afterwards rather than using it within Brave
• ensured that Create QR code for this image appears in the context menu when right clicking on images
  • scanned it with an iOS device and ensured that the correct page is being loaded
  • ensured that you can download the QR image and use it afterwards rather than using it within Brave

Example	Example	Example