Pulp

Currently, pulplift uses the default "pulp" user to install everything, so that user must be used to run any pulp-manager commands. The aliases like `pclean` do not work because of this problem.

In the meantime, there is a workaround for this:

sudo -u pulp /venv/path/pulp-manager <command>

ansible-pulp3 has a variable `pulp_user` that defaults to "pulp". We can override the default in the playbook, but we will also need to make some adjustments for the user's home dir and fix other problems that might arise.