Megabytes have shown to be a bit clumsy in the configuration files, so
simply switch to the more useful Gigabytes unit.

Fixes #39

Refers to #31

Refers to #6, #25

Fixes #31

By removing the AdminDebugLog() method we're basically done with
switching to NLog for logging and therefore this closes #3.

All projects (and namespaces) should start with an "ATx" prefix, having
a capital "AT" and a lowercase "x".

Refers to #3

All outputs of any kind of duration should be using a human readable
variant of the time span.

Fixes #25

Since they only depend on current configuration settings they should as
well be accessible through the config class. This way they can be used
in a consistent fashion across different projects.

This allows us to re-use the summary method in other tools like the tray
application.

This can probably safely be removed once the logging has stabilized and
is tested in production.

Refers to #3

Refers to #3

Currently this is almost entirely untested and configuration for email
notifications is yet to be done.

Refers to #3

Plus make sure to not attempting to send the mail message if the
account name can't be resolved to an email address.

Fixes #8

Corresponds to "autotransfer-v1".