Merge in staging-v2.0.0

.gitignore

.gitlab-ci.yml

CMakeLists.txt

README.md

VERSION

cmake/options.cmake

containers/CMakeLists.txt

containers/builder/Dockerfile

containers/builder/Makefile

containers/builder/config.env

containers/builder/eic_builder.def

containers/builder/version.sh

containers/docker/Dockerfile

containers/docker/HepPDT-3.04.01.tar.gz

containers/docker/usage.sh

containers/docker/version.sh

containers/release/Dockerfile

containers/release/Makefile

containers/release/config.env

containers/release/eic.def