Allow configuring the delimiter for SECURITY_PROVIDERS

[dmikusa]

Describe the Enhancement

Make the delimiter configurable with a space being the default. You could then override that with a comma. I think that would be sufficient to make things work with SECURITY_PROVIDERS.

Possible Solution

Right now it is a space, make this configurable but default to a space for backward compatibility.

Motivation

A space works well in a lot of cases, but some security providers like bouncy castle require arguments. These are space separated which breaks the buildpack mechanism for setting security providers. If we allow a different delimiter to be set then you could use a comma or pipe and work around this limitation. See #259 for more details.