List deleted API for apps, groups, and users

[tsologub]

Add support for listing deleted applications, groups, and users. (i.e. basically this page)

Notes to the reviewer:
As

unexpected status 400 with OData error: Request_BadRequest: The service does not currently support writes of mail-enabled groups. Please ensure that the mail-enablement property is unset and the security-enablement property is set.

is not yet supported at the moment and it is a long-desired feature - I left the "Groups part" without a test case. I have tested this manually by creating+deleting O365 group and afterward executing GroupsClient.ListDeleted().

[manicminer]

Hi @tsologub, thanks for this PR! This mostly LGTM - I've pushed a change to the ListDeleted methods so that they return slices of their respective struct type, and added a check to each of the tests to verify the recently deleted object is returned. I also added some missing fields for Applications and Users; there are still some short but these can be added later.

[tsologub]

Thanks for reviewing @manicminer.

I've pushed a change to the ListDeleted methods so that they return slices of their respective struct type,

This totally makes sense. Now I wonder why I went with the slice of ids instead of the type. 🤔

and added a check to each of the tests to verify the recently deleted object is returned

Perfect. Even more robust tests.