Feature/3942 embed project

Liked @paulkaplan’s suggestion that the property get renamed `showBranding` as we use ‘embedded’ in multiple ways that would get confusing.

The embedded project view is ‘playerOnly’, ‘fullscreen’ and ‘showBranding’.

Remove default state for extensions that haven't been added to a new project yet

Update chromedriver to the latest version 

Update scratch-vm to the latest version 

Update scratch-blocks to the latest version 

Add an alert that is shown when you first add a cloud variable

chore(package): update scratch-vm to version 0.2.0-prerelease.2018120…

Update scratch-blocks to the latest version 

Always show stage in large mode when isPlayerOnly.

Prevent thumbnails from containing the video layer

Fixes 2 related issues:
1. The stage shrinking to 85% based on responsive stylings, which shouldn't happen when embedded in player only
2. When you click "small stage mode" in the editor then switch back to the project page view, it shouldn't show with small stage mode.

Closes #3935

Has cloud permission

Update scratch-paint to the latest version 

Fix stage wrapper not setting dir="ltr/rtl" property, buttons look wrong

Update scratch-blocks to the latest version 

Include polyfill for promise.finally so Edge can load projects

Cloud Variable Rate Limit

Update scratch-blocks to the latest version 

Update scratch-vm to the latest version 

Update scratch-l10n dependency