Support for OpenPGL project

[jfpanisset]

The Open Path Guiding Library is now a sandbox stage ASWF project:

https://github.com/OpenPathGuidingLibrary/openpgl

In order to add a ci-openpgl build container, we need to:

• identify the list of dependencies
• create a Conan recipe to build it as a Conan package

A custom recipe can be developed for this project, but it would be great to see a generic recipe submitted to the Conan Center Index:

https://github.com/conan-io/conan-center-index