Gui 1162 UX review for adding VPC support on the instance launch and launch config wizards

https://eucalyptus.atlassian.net/browse/GUI-1162
https://eucalyptus.atlassian.net/browse/GUI-1228
https://eucalyptus.atlassian.net/browse/GUI-1229
adjusted to use 'associate_public_ip_address = True if associate_public_ip_address_param == 'true' else False'