Add remove/restore scripts for nested .git folder

[maxxcrawford]

Summary

Add scripts to help dev process

• dev: The /src/_locales/.github folder causes web-ext run to fail when running the npm run dev script. This folder removal isn't tracked or surfaced during local dev work when working from the root directory.
• build This script runs web-ext build. There was an error when running when running npm run package that would call for this missing command.

Testing

dev script:

• Checkout PR
• Run $ npm run dev
• Expected: The extension should run locally without any console errors

build script:

• Checkout PR
• Run $ npm run package
• Expected: There should be a new local .zip of the add-on in the /web-ext-artifacts folder folder and that file/folder should not be tracked in git.
• Run $ git status to confirm new .zip file is not tracked