Incremental backoff on loading SSL cert

Try for 16 seconds (14 loops) to load the SSL certificate.

On the first time through the loop, create self-signed certificate
if configured to do so.

This also splits the generation of the self-signed certificate into
a separate function.

While we're here, split the new SSL epoch out into a separate function
as well, and explicitly call it when we create a new self-signed
cert. This at least partially fixes the epoch thing, but there's
still the possibility of creating it multiple times in the same
second... the file date isn't really enough.