CB-7190: Add browserify support in cordova-lib/cordova-cli

https://issues.apache.org/jira/browse/CB-7190
We added the browserify checks to install & uninstall because ```cordova plugin add/rm``` directly calls ```plugman.raw.install/uninstall```. It skips going through ```plugman.js``` and therefore https://github.com/surajpindoria/cordova-lib/blob/browserify/cordova-lib/src/plugman/plugman.js#L131 never runs.

A better fix then adding these multiple checks would be to get ```cordova plugin add/rm``` to run ```plugman.js```. We haven't explored this yet though.

Once ```prepare-browserify``` becomes the default way of doing things, we can remove the old prepare and remove these checks.