Now admins can choose a title for their About and Privacy pages; now
editable through the instance page editor.
This adds `title` and `content_type` fields to the `appcontent` table,
requiring a migration by running `writefreely --migrate`
The content_type field specifies that items we're currently storing in
this table are all "page"s; queries for fetching these have been updated
to filter for this type. In the future, this field will be used to
indicate when an item is a stylesheet (ref T563) or other supported
type.
Ref T566
This adds a "Pages" section to the admin part of the site, and enables
admins to edit the pre-defined About and Privacy pages there, instead of
on the dashboard itself.
It also restructures how these pages get sent around in the backend and
lays the groundwork for dynamically adding static pages. The backend
changes were made with more customization in mind, such as an
instance-wide custom stylesheet (T563).
Ref T566
Matt Baer