This supports a new `monetization_pointer` collection attribute.
When present, we include the `monetization` meta tag on all
collection pages.

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

This fixes a template rendering issue caused by bad references to $.Host
in pinned posts links on single-user instances.

Closes #207

the change to take a hostname in Post.CanonicalURL broke a few template
using that function. This adds a Hostname string to the Post being
passed to templates and passes it to calls to Post.CanonicalURL

- 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

Previously, the URL of the dynamically-added pinned post on a
single-user instance would include the username, causing the link to go
to a non-existent page. This fixes that.

This included files.writeas.org paths and other Write.as-specific logic.

Might as well do this right away, we're here anyway.

It now loads unconditionally and highlights all code blocks.

TODO: optimize to not load when there are no blocks

This is a first stab at having a configurable code highlighting option,
similar to the MathJax rendering option. This change makes a checkbox
in the settings for code highlighting using the highlightjs.org
library.
What works: code highlighting in multi-user env is like I would
expect. single and anon(?) needs work

Things to resolve/consider:
- does the .IsCode test for code highlighting need to stay? At least
this and that should use the same version of the highlight.js lib.
- can the common templating part be 'included' somehow?
- the anon vs single-user vs multi-user code is not completely
clear (to me)
- bring js to local instead of cloudfare cdn (perhaps combine with
MathJax)

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