Add TMPDIR global to vm install script for security purposes

Dick Jense shared this problem 39 days ago

For safety purposes, /tmp is usually mounted as noexec. This generates an error during installation of VMmanager, as Docker requires some files within this directory to be executable. Therefore, please add a TMPDIR global to the Docker script, to avoid having to (temporarily) remount /tmp as executable. This is a security issue.

See for reference.