GUI-907: Timestamp fixes for various detail pages and launch configs landing page

- Fixes timestamps on instance, volume, snapshot, IAM user, IAM group, and launch config detail pages by convert UTC-aware ISO-8601 formatted timestamps into local time zone of user agent
- Fixes timestamps on launch configs landing page by convert created timestamp to timezone-aware datetime objects when formatting as ISO-8601 strings

Fixes https://eucalyptus.atlassian.net/browse/GUI-907