Previously, we'd show the raw HTML entities in the summaries of Draft
posts, instead of rendering them. This fixes that.

This changes all variables and functions from using Suspend{ed} to using
Silence{d} as well as documentation, errors and logging.

- update error messages to be correct
- move suspended message into template and include for other pages
- check suspended status on all relevant pages and show message if
logged in user is suspended.
- fix possible nil pointer error
- remove changes to db schema files
- add version comment to migration
- add UserStatus type with UserActive and UserSuspended
- change database table to use status column instead of suspended
- update toggle suspended handler to be toggle status in prep for
possible future inclusion of further user statuses

- This removes copy mentioning the Blogs page, which isn't used on
  single-user instances
- This fixes the "Start writing" link, which on a single-user instance
  would've gone to the blog index, rather than the editor

- New editor nav
- New backend nav
- Support for drafts
- Different footers on backend