Refactor: prepare for additional user creation steps.
Whitespace removal.
Refactor; create named administrative user.

This patch cleans up the CouchDB user/password creation process, and adds two
steps aimed at creating a named administrative user alongside the ordinary
`admin` user. I still need to figure out how to store the most recent
administrative username, so we can remove any old account if the process is
repeated using a different name.

Eventually, we may want to skip creation of the `admin` user entirely. It's
useful to have a known/fixed account name if the chosen user name is forgotten,
but it's potentially a brute-force password guessing target.
Delete unknown users: mostly finished.

This makes the user creation process repeatable, by seeking out and deleting any
previously-created administrative users and/or user documents. The latter isn't
yet working, because a `rev` is required for a successful user `DELETE`
operation. The next commit should solve that problem, as well as turn on the
view regeneration code. After that, the backend code should be done, and all
that'll be left is some minor UI reworking.