Merge branch 'pkg/add-to-master' into 'master'

.gitattributes

.gitlab-ci.yml

.gitlab-ci/build-and-test.sh

.gitlab-ci/packaging-exclude

.gitlab-ci/packaging.yml

CMakeLists.txt

cmake/Nektar++Config.cmake.in

cmake/ThirdPartyCCM.cmake

docker/packaging/Dockerfile-centos-7

docker/packaging/Dockerfile-centos-8

docker/packaging/Dockerfile-debian-bullseye

docker/packaging/Dockerfile-debian-buster

docker/packaging/Dockerfile-debian-stretch

docker/packaging/Dockerfile-debian-unstable

docker/packaging/Dockerfile-fedora-33

docker/packaging/Dockerfile-fedora-34

docker/packaging/Dockerfile-fedora-35

docker/packaging/Dockerfile-source-archive

docker/packaging/Dockerfile-source-doc

docker/packaging/Dockerfile-ubuntu-bionic