* Add datetime-diff implementation for athena

* Don't run some tests for drivers not supporting timestamptz

* Fix for date types

* Use date-trunc helper

* Add comment about Athena's timestamp with time zone type

* Add datetime-diff-time-zones-athena-test

* Fix typo

* Fix typo

* Rewrite comment

* Tidying

* Add athena-datetime-diff-mixed-types-test

* Fix typo

* Adjust comments + formatting

* Adjust comments

* Format SQL query

* Align requires