Angular services should be loaded first

Some Angular providers may be needed at config state. So the services files must be loaded before the other JS files, especially the config ones.

But the `assets.js` object in `config/env/all.js` makes `module.exports.getJavaScriptAssets()` in `config/config.js` load all JS assets alphabetically.

This PR fixes this and makes the JS files being loaded in this order :
1. Angular lib files
2. App config (`public/config.js`)
3. App init  (`public/application.js`)
4. Modules declarations  (`public/modules/*/*.module.js`)
5. Modules services (`public/modules/*/services/*.js`)
6. The remainder...