fix: remove docker from defaults, fix cliphist-image ordering cycle

Docker is a dev dependency, not a desktop environment default. Remove
from package list, archinstall config, services and README.

Fix systemd ordering cycle that prevented cliphist-image from starting:
cliphist-text had After=graphical-session.target which combined with
PartOf= and cliphist-image's After=cliphist-text created a cycle.

config/user_configuration.json

@@ -43,8 +43,6 @@
         "pipewire-jack",
         "pipewire-pulse",
         "wireplumber",
-        "docker",
-        "docker-compose",
         "fwupd",
         "ufw",
         "greetd",
@@ -68,7 +66,6 @@
     "services": [
         "NetworkManager",
         "bluetooth",
-        "docker",
         "greetd",
         "systemd-timesyncd",
         "ufw"