PVC implementation

[mtompkins]

Thank you for your work on the traefik chart.

The choice is bifurcating the PVC volumes into two sections seems quite counterintuitive. Specifically, you have a section of persistence and a subsequent part of the chart that allows volumes.

I think some consideration should be given to a consolidated and proper ability to add volumes in the latter section, including the user's choice of multiple PVCs if desired. I do not see a seamless was to do this at this time. For example, a user may want to store the acme.json as well as persist logs on a host in a separate location.

If I'm incorrect in the chart templates ability to parse multiple preexisting PVCs, I welcome correction.