Update mac installer update

[simonhong]

Add background image
Add volume icons but not working.
--icon option of pkg-dmg seems broken now.
chromium issue - https://bugs.chromium.org/p/chromium/issues/detail?id=970374

Fix brave/brave-browser#1105

To position icon in mounted finder window, .DS_Store should be used. It has some attributes for window size/position, background image and icon position of app and application link.

To generate .DS_Store for each channel, https://github.com/andreyvit/create-dmg is used.
I used below command line for generating them.
create-dmg --volname "Brave Browser Nightly" --volicon installer-nightly.icns --background ./dmg-background.png --window-size 602 350 --icon Brave\ Browser\ Nightly.app 150 155 --icon Applications 430 150 --format UDBZ Brave\ Browser\ Nightly.dmg ./source_dir/

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Verified that these changes build without errors on
  • Android
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that these changes pass automated tests (unit, browser, security tests) on
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that all lint errors/warnings are resolved (npm run lint)
• Ran git rebase master (if needed).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed.
• Add appropriate QA labels (QA/Yes or QA/No) to include the closed issue in milestone
• Public documentation has been updated as necessary. For instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protection-Mode
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-compatibility-issues-with-tracking-protection
  • https://github.com/brave/brave-browser/wiki/QA-Guide

Test Plan:

yarn create_dist Release --channel=nightly --skip_signing and run dmg in src/out/Release/

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions
• Verify test plan is specified in PR before merging to source

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on.
• All relevant documentation has been updated.

[bsclifton]

Tested and this works great! The volume icon even shows up for me:

Great job! 😄👍

[bsclifton]

Thanks for capturing the steps on how you made the .DS_Store also! ❤️