Admin asset resources minify to single file

[nadar]

No description provided.

[nadar]

https://github.com/matthiasmullie/minify instead of using those java yui compressors

[nadar]

@TheMaaarc Would it be possible to add the javascript files into the gulp workflow, so we can reduce the "mutli request loadtime" to just a few js files?

As we have decided to NOT using bower as it would slow down the composer update (and other reasons). So now we can maintain the js by our self and add them to js workflow in order to minify them into one single file.

[nadar]

@TheMaaarc Except of the angular locale files: https://github.com/luyadev/luya/tree/master/modules/admin/src/resources/bowervendor/angular-i18n

[nadar]

@TheMaaarc Please add a changelog entry, update the guide https://github.com/luyadev/luya/blob/master/docs/guide/luya-guideline.md#admin-module-css-informations and close the issue. Thanks