Add pipeline for building releases

[orhoj]

Purpose

Build the prod build and the development build in a GitHub action. The files are just uploaded to GitHub for now but will ensure consist builds, and we can stop building releases locally. An additional step would be to publish the release to the Chrome extension store.

Changes

• GitHub action that builds and uploads the browser wallet for production and development.

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG.