Update Windows installer icon and install image (similar to what muon had)

[srirambv]

Description

Similar to #1105, Windows installer should be updated as well since Windows is our biggest user base as compared to the other two platforms.

Steps to Reproduce

1. Download Brave setup from brave.com/download
2. See the 16bit pixelated setup installer icon
3. Close your eyes and run the setup so as to not to see the boring Chromium installer window

Actual result:

Expected result:

Similar to Muon or something better

Reproduces how often:

Easy

Brave version (brave://version info)

All

Version/Channel Information:

• Can you reproduce this issue with the current release? Yes
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the dev channel? Yes
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? N/A
• Does the issue resolve itself when disabling Brave Rewards? N/A
• Is the issue reproducible on the latest version of Chrome? N/A

Miscellaneous Information:

cc: @rossmoody

[kjozwiak]

@rebron is there any plans in the pipeline to "Bravify" the window installers now that we've released 1.0? We've had #1105 on macOS for some time now. Would be nice to get the executables looking good for the largest platform.

[aguscruiz]

Design added:
https://www.figma.com/file/vQh4syYlKU7cEzcpBGMdwS/Windows-Installer-Splash-screen?type=design&node-id=0%3A227&mode=design&t=20A7Ym5d1lJnmqO9-1