Add guide about upcoming HashiCorp Vault integration

[skyllarr]

No description provided.

[darranl]

Maybe we can adjust a little so users can use the version we are publishing on a regular basis, then maybe use the "build yourself" instructions to the end for the users that want that?

[skyllarr]

Maybe we can adjust a little so users can use the version we are publishing on a regular basis, then maybe use the "build yourself" instructions to the end for the users that want that?

Ah yes this was written before we published to maven central. I've updated the post to mention latest maven central version. And I've put the building from repository under getting involved section at the end

[skyllarr]

I've changed this PR to be a draft. I will submit a blog post link instead of a guide for the in progress work. Once we have a first released version, I will reopen this guide PR.