Summary

Add support in environments for external configuration files obtained from a URL.

Rationale

Spack currently assumes these files reside on the local file system but projects and facilities put a lot of effort into defining standard, or base, configuration files for their systems. Spack should make it easier to use configuration files from the web.

Description

Configuration files obtained from remote repositories should be supported.

Additional information

$ spack --version
0.17.1-1109-d4ca803fc5

General information

• I have run spack --version and reported the version of Spack
• I have searched the issues of this repo and believe this is not a duplicate