Description of problem:
When a considerable number of unique-user GUI sessions are logged into a system, login/ logout can take upwards of 2 minutes as polkit performs an authorization check for packagekit, NetworkManager and boltd for every user at once.

Version-Release number of selected component (if applicable):
Red Hat Enterprise Linux 8
polkit-0.115-15.el8.x86_64
gnome-session-3.28.1-20.el8_8.x86_64

How reproducible:
Customer is able to consistently reproduce behavior.

Steps to Reproduce:
1. Have a considerable number of unique-user GUI sessions active (XDMCP/VNC can be used, around 25-40 users).
2. Attempt to login to a new session.
3. Attempt to logout of a currently running session.

Actual results:
Login/Logout takes up to 2 minutes to occur.

Expected results:
Login/Logout should be near immediate (less than 5 seconds).

Additional info:
Due to the large amount of users needed to be actively logged into a GUI session on a single system, I am unable to test this myself.

I have selected polkit-gnome as component as both gnome and polkit are involved with behavior. Please assign a different component if needed.