Auto install bundle

Automatically install extensions "bundled" with installer on startup.

**Issues**:
* Should appReady in ExtensionManger be used instead?
* Terminology: folder name and location

cc @dangoor @peterflynn 

This is for #9233 
nit: might be nicer to say `dirPath = FileUtils.getDirectoryPath(FileUtils.getNativeBracketsDirectoryPath()) + "bundles/";