* iam_user: use AnsibleAWSModule.client to fetch connection rather than C&P code
* iam_role: Add deprecation warning so we can switch purge_polices default behaviour from true to false
* iam_user/role/group: Rename 'managed_policy' and 'purge_policy'
Rename from singluar to plural (we accept a *list* of policies), and add aliases for the old values.
* Cleanup documentation
* Changelog
