Localize redactor

To be able to localize Redactor with the current `$this->requireAsset('redactor');` we need to update the redactor asset group.
So, in this pull request we have:

1. Some PRS-2 coding style fixes

2. Implemented assets de-registrations (when switching from a language to another one we have to reset the components of the redactor asset)

3. Added a new asset type: InlineJavascriptAsset. This is required since to activate a language we have to write a line of code like `$.Redactor.opts.lang = 'language code';``

4. Added (and normalized) the Redactor language files

5. Update the 'redactor' asset group when setting/switching a language