dms-v0.2.1-alpha.0.121

[DMS-92] Basic eTag creation (#381)

* Generate Etag with LastModifiedDate and return in header after POST

* ignore etag in e2e expected body comparisons

* E2E coverage of basic etag

* etag update on cascading updates

* always check etag

* mimic ods api etag format

* rename middleware

* unit test

* Remove unnecessary backend code