Adding Sherlock CPU target for travis

[jafranc]

Companion PR with

https://github.com/GEOSX/thirdPartyLibs/pull/193

adding a target for Sherlock Stanford cluster configuration: (CPU-version)

• centos 7.9.2009
• gcc-10.1.0
• openmpi 4.1.2
• openblas 0.3.10 (GPU-version)
• cuda11.5.0 [Debug only - Release overtime]