CI: Add Frontier nightly builds
After the end of ECP we lost our precious VTK-m OLCF CI infrastructure which compromised CI builds in Ascent (Summit) and Crusher (Frontier). This CI infrastructure allowed us to maintain compatibility with these systems.
Earlier this year I applied for VTK-m to be included in a list of pilot post-ECP projects which wished to retain access to this OLCF CI infrastructure. After a lengthy email conversation with the OLCF sysadmin team, VTK-m has finally been allowed access to the OLCF CI infrastructure. We now have 5000 hours of computing time until EOY in OLCF Frontier in a project named ums033.
backport: release