vpki-proxy is a quick & dirty configurable TLS proxy which uses Let's Encrypt
(via rsc.io/letsencrypt) to retrieve certificates for
the services. The usage of the vpki library means that
it should be trivial to set up vault as a cert provider as well. I intend to do
this in the near term.
This proxy will also export Prometheus metrics if an
IP prefix is given. This should be extended in the future to allow more
flexibility.