Cache bust cordova_plugins.js

# Feature Request

## Motivation Behind Feature
If we leverage browser caching. Then the `cordova_plugins.js` should be cached by the browser for as long as possible. Therefore it would be a nice feature to have `cordova_plugins.js` cache bustable

## Feature Description
```javascript
njectIfNecessary('cordova/plugin_list', pathPrefix + 'cordova_plugins.js?' + hash, function () {
```
An easy way of doing it is to add a query string to the request for `cordova_plugins.js`
`hash` where the hash could be generated on build from the plugins list

Start by locating where cordova_plugins.js is generated from the plugins list and where it is loaded through the cordova/plugin_list entry point. Read the surrounding build and loading flow before deciding how the hash is produced. Done means the generated request includes a stable plugin-list hash so browser caching is refreshed when the list changes.

Written by the indexing model from the issue text.