This fixes a condition where an intermittent db connection could cause
invalid site settings to be stored
It also removes a catch all we had.
Somewhere around Rails 5 `db:create` started wanting full environment
this is a problem for Discourse since it needs to boot up data from the
db.
This removes the catch all and surgically adds a db / redis bypass to
db:create task.
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
