For users who can "customize ckeditor", settings can be overwitten with unwanted values

Problem/Motivation

On a client site we ran into an issue where we wanted to update the width for all users, but the width would supposedly not change (for the admin user) as this user had "customize ckeditor" permissions. This meant CKeditor would load the default width (100%) everywhere and ignore the values in the profile, while we never explicitly intended to override the editor width.

The reason for this is that when saving a user page with "customize ckeditor" permissions, the default values are used as the ones to override the profile values with, which is not what we want as the user never explicitly defined those.

Proposed resolution

Unless a value has been specifically defined by a user, we should stop overriding the profile values on a per user level, and use the value defined in the profile instead.

Remaining tasks

Review patch

User interface changes

Offer a "use site default" radio on all customizable options:

API changes

None