Adds JcloudsLocation.AUTO_ASSIGN_FLOATING_IP

- name more consist with jclouds name.
- used for CloudStackTemplateOption.setupStaticNat (hence removing nova
  from config key name)
- deprecates nova-specific AUTO_CREATE_FLOATING_IPS
Merge pull request #1359 from aledsage/refactor/JcloudsLocation.AUTO_ASSIGN_FLOATING_IP

Adds JcloudsLocation.AUTO_ASSIGN_FLOATING_IP