notifier: Notifier now checks if delay value exceeds 10 days. Fixed problem with overruning days in at command parameter.

By using the busybox one unconditionally

For distribution purposes, mostly.

At least for now. We want to download and generate it on the spot in
future and renew it.

This is equivalent to revocation in our case.

We need to rotate it

Having them unquoted is possibly insecure. Also, it kept losing newlines
in the messages.

Not all servers support login, and some support better. Use the best one
available.

Always sent, but used only in testing purposes.

Using == as test condition is bashism. While ash is willing to swallow
that, there are shells that aren't.

* Directory to operate on
* Flag to trigger sending right away