GUI-337: IAM Policy Generator - Conditions

Adds the following for https://eucalyptus.atlassian.net/browse/GUI-337 ...

- Allow one or more conditions to added to (or removed from) a policy statement
- When a condition is removed, only the unique condition operator/key combination is removed from the statement
- Fixes race conditions initializing Chosen widgets in the resource select fields
- Minor layout changes to allow more space for resource and condition inputs

Notes:
- Implemented "Add Conditions" as an expando since the section is optional and it takes a fair amount of space when expanded
- The condition value is left as an open text field for now due to validation and implementation constraints