#8 Non-editable display components

[Mark Howell]

Non-editable display components (such as Modules,
Columns and ModuleLayouts) can be setup and configured
by admins to always appear on users' displays.

Uses for this include: having a Module always visible
to a user at, say, the top spot of the left-most Column
to display site news, navigation information or spam,
or having the "splash page" for all users of a certain
role be one configured by the administrator, and only
secondary (or tertiary, etc) layouts can be customized
by the user.

There is previous support for non-user-editable
Modules, but that methodology has been rethought. It
was (is) too global in scope to be useful in the
current context.

Implications/changes:
Currently, Modules, Columns and ModuleLayouts are all
tied to their parent via their unique Id, not their
sequence. In order to have, say, a "floating" top left
Module, that Module would have to be associated with
the Column with sequence 1, not Id 1234, like it
currently is. Perhaps it would use negative Module
sequence number to always keep it at the top, otherwise
the regular Column editing scheme would have to be
updated. We'll see.