Preserve tag key case by only calling camel_dict_to_snake_dict once,
before the tags are added.
Don't call assert_policy_shape as it seems to fail
Use aws_caller_info in the test suite now that it exists rather
than running `aws sts get_caller_identity`
Ensure that calls using `grant_types` can also use key aliases
* Fix TagName and TagValue in aws_kms
Fixes#53061
* Improve test suite to check for tags
Also fixed some obvious failures, need to run the test suite from time
to time!
* Allow creation and deletion of keys (deletion just schedules for
deletion, recreating an old key is just cancelling its deletion)
* Allow grants to be set, thus enabling encryption contexts to be
used with keys
* Allow tags to be added and modified
* Add testing for KMS module
* Tidy up aws_kms module to latest standards
