Add basic GitHub workflows and templates

.github/CONTRIBUTING.md

.github/ISSUE_TEMPLATE/bug_report.md

.github/ISSUE_TEMPLATE/config.yml

.github/ISSUE_TEMPLATE/feature_request.md

.github/PULL_REQUEST_TEMPLATE/pull_request_template.md

.github/workflows/linux-eic-shell.yml

.github/workflows/linux-lcg.yml

.github/workflows/macos-lcg.yml

src/B0Preshower_geo.cpp

src/B0Tracker_geo.cpp

src/CylindricalDipoleMagnet_geo.cpp

src/ForwardRomanPot_geo.cpp

src/OffMomentumTracker_geo.cpp

src/TaggerCalWSi_geo.cpp

src/TaggerTracker_geo.cpp

src/ZeroDegreeCalorimeterEcalWSciFi_geo.cpp

src/ZeroDegreeCalorimeterSampling_geo.cpp