Add pipeline to convert geometry to gltf

**Is your feature request related to a problem? Please describe.**
The Phoenix event display requires a gltf file as input.

**Describe the solution you'd like**
We should automatically export a gltf file from the geometry(ies) in CI.

**Describe alternatives you've considered**
This could be done by hand....

**Additional context**
Ref: https://github.com/eic/root-to-gltf-exporter and https://github.com/HSF/root_cern-To_gltf-Exporter

**Why is this harder than it looks?**
The root-to-gltf-exporter is written in typescript and requires a web browser.