Move tljh-config symlink to /usr/bin

Removes a lot of 'sudo -E' usage, and eventually should
let us get rid of the $PATH override for jupyterhub-admins,
which arguably is less secure than just dropping stuff into
/usr/bin

Also remove sudo -E from apt and mkdir calls. Not necessary.

integration-tests/test_hub.py

@@ -12,7 +12,7 @@ import sys
 
 # Use sudo to invoke it, since this is how users invoke it.
 # This catches issues with PATH
-TLJH_CONFIG_PATH = ['sudo', '-E', 'tljh-config']
+TLJH_CONFIG_PATH = ['sudo', 'tljh-config']
 
 def test_hub_up():
     r = requests.get('http://127.0.0.1')