Proposal: Include page level in page unicode method

[Andrew Schoen]

I'd like to propose that we add back in the page level to the page unicode method.  This is incredibly helpful when using the link plug-in and selecting a page.  I have a site with over 500+ pages and without some indication of the level it would be impossible to pick a page.

[Jonas Obrist]

I just noticed that there's actually a setting for this, CMS_TITLE_CHARACTER, which however is not used at all. Maybe we can revive that.

[Andrew Schoen]

Was brought to my attention that you can use PageField in
cms.models.fields to get what I want. We should use this same field
in all the built-in plug-ins, like the link plug-in, that allow you to
pick a page from the CMS.