feat: make assets folder name configurable

[jcesarmobile]

Feature Request

Motivation Behind Feature

cordova-ios has a wwwFolderName to configure the name of the folder where the cordova app is loaded (defaults to www). On Android the www is hardcoded in several places.

Feature Description

note that on cordova-ios it's only configurable with code, so not meant to be changed from config.xml, is for when integrating cordova into native projects.

Alternatives or Workarounds