REST client support for PEM certs

[ppf2]

From a quick chat with @jaymode , the current high level rest client implementation only supports referencing Java keystores and it will require additional code/libraries to be implemented in order for users to directly reference PEM certs. This is an enhancement request to provide an option to reference PEM certs directly when using the client.

[javanna]

I updated title and labels, this is about the low-level REST client rather than the high level one.

[jordansissel]

@ppf2 To clarify, just certificates, right? Not keys?

[ppf2]

For this use case, yes, for specifying ca cert bundle.

[dakrone]

This has been open for quite a while, and we haven't made much progress on this due to focus in other areas. For now I'm going to close this as something we aren't planning on implementing. We can re-open it later if needed.