Initial check-in: package configuration command.
Don't use logrotate with gardener.

Gardener has its own built-in log rotation; using logrotate with it will produce
comical results at best.
Remove hard-coded medic-core logrotate directory.

Packages that use the `logrotate_install` facility exported by `medic-core` will
get linked in to `/etc/logrotate.d`; there's no need to hard-code a package name
or directory anymore.
Package-specific configuration `->` envdir format.

Remove the weird package-specific `configuration` directory, and replace it with
an `envdir`-style directory of environment variable name/value pairs called
`env`. This directory will sit in `/srv/settings/$package/env`, and be used for
any post-deployment configuration of package-specific options. We currently just
use it to set `NODE_ENV`, but it'll eventually be useful for feeding options in
to configuration-file templates.
Fix `medic-transport` logrotate configuration.

This permission change and fixed typo should allow `logrotate` to run properly
for medic-transport once again. This is just a minimal fix; I'll do a review of
permissions/ownership across all of the packages to make sure we're setting
them properly.