nodecfg: Sort the list of names for host type

It looks better if we present a list of sorted options. This will
automatically sort new names if they are added in the future.

The list now should look like:

  (1) ci_server - Qt Project CI system server (Jenkins <-> Gerrit integration)
  (2) ci_tester - Qt Project CI tester, performing Qt compilation and autotests
  (3) network_test_server - Network test server, used for some QtNetwork autotests (qt-test-server.qt-test-net)
  (4) packaging_server - Qt Project packaging server
  (5) packaging_tester - Qt Project Packaging tester, performing Qt compilation and autotests

Change-Id: Iccba5482f9e5e75b61ef6a6fd5cb0f97424f6e52
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>
Reviewed-by: Simo Fält <simo.falt@digia.com>