make new stage for building the generator in ci

2 jobs for adi-dev in 13 seconds
Name Stage Failure
failed
EMAM2CppBuild Build
Executing "step_script" stage of the job script
$ which ssh-agent || ( apt-get update -y && apt-get install openssh-client -y )
/usr/bin/ssh-agent
$ eval $(ssh-agent -s)
Agent pid 19
$ ssh-add <(echo "$GITHUB_SSH_PRIV_KEY")
Error loading key "/dev/fd/63": invalid format
Cleaning up file based variables
ERROR: Job failed: exit code 1