Speed up CI builds: cache v4, google-test caching, parallel C++ compiles - #1248

Speed up CI builds: cache v4, google-test caching, parallel C++ compiles#1248

mickem with Copilot wants to merge 5 commits into

mainmickem/nscp:mainfrom

copilot/improve-build-speedmickem/nscp:copilot/improve-build-speedCopy head branch name to clipboard