Separate distribution channels for basic / full / standard preset

[mlewand]

As a result of discussion in https://github.com/ckeditor/ckeditor-releases/issues/41 we got a better way of handling releases.

The idea is to keep separate endpoints for each preset:

• keep ckeditor/ckeditor pointing at standard-all preset
• ckeditor/ckeditor-basic
• ckeditor/ckeditor-standard
• ckeditor/ckeditor-full

Also we'd have to create a separate repo for each preset, and update our release script to do this automatically.

[f1ames]

Closing as not really relevant anymore as it seems we are happy we the things the way there are here.