Alias auth-get-sso-cookie in CS8 image

[aperloff]

Instead of installing auth-get-sso-cookie into the CS8 image directly create an alias to the binary on the LCG software. For example:

alias auth-get-sso-cookie=`/cvmfs/sft.cern.ch/lcg/releases/LCG_102/auth_get_sso_cookie/1.5.0-1/x86_64-centos7-gcc8-opt/bin/auth-get-sso-cookie`

We will need to know something about the system (i.e. gcc version and os version) so it might be best to add this to the .bashrc file.

[aperloff]

The tools use #!/usr/bin/env python, but CS8 doesn't come with a link to python, which is more traditionally referring to python2. Therefore, for maximum compatibility, we will make a link so that these tools will work.