Use the new Site.global_type column

...instead of global_http_status. This also includes Transition's
current db/structure.sql, which has some bits of accidentally-committed
collation diff, but since that should be sorted out in transition first
I've copied it all over as-is.
Merge pull request #76 from alphagov/use_site_global_type

Use the new Site.global_type column
Treat unresolved mappings as archived

* No decision has been made
* Rack returns a 410
Merge pull request #77 from alphagov/unresolved-defaults-to-archive

Treat unresolved mappings as archived