Custom Server Environment Variables

It would be handy to securely create and store custom environment variables on a server basis to be used during SSH commands and Config files.

We are currently restricted to only what is available:

https://www.deployhq.com/support/projects/variables

This would then avoid need to create individual config files per server. Instead, we only need one and ensure the environment variables are set. This is a pretty common setup in other CI/CD providers (ie: github, gitlab, bitbucket, etc)