Added possibility to run a double buildtree for both EOS and CTA.

continuousintegration/buildtree_runner/prepareImage.sh

...tegration/buildtree_runner/prepareImageStage2b-scripts.sh

...n/docker/ctafrontend/cc7/buildtree-stage1-rpms/Dockerfile

...tafrontend/cc7/doublebuildtree-stage2b-scripts/Dockerfile

...egration/docker/ctafrontend/cc7/opt/run/bin/mkSymlinks.sh

continuousintegration/orchestration/create_instance.sh

continuousintegration/orchestration/pod-client.yaml

continuousintegration/orchestration/pod-ctacli.yaml

continuousintegration/orchestration/pod-ctaeos.yaml

continuousintegration/orchestration/pod-ctafrontend.yaml

continuousintegration/orchestration/pod-init.yaml

continuousintegration/orchestration/pod-tpsrv.yaml

continuousintegration/orchestration/pod-tpsrv01.yaml

continuousintegration/orchestration/pod-tpsrv02.yaml