[Zurich] Add deleted column to body table

This is so Zurich can mark certain external bodies (which may already
have problems assigned to them) as deleted, without *actually* deleting
them.
[Zurich] Remove super user check from body-form

The logic has changes, so it's now only the superuser that can access
this whole form, so there is no need to be this granular.
[Zurich] Add schema migration 0029 to bin/update-schema
[Zurich] Update schema.sql with body.deleted column
[Zurich] Update DB/Result/Body.pm schema