Improvement suggestions

[OgreTransporter]

Allow user search by properties, see https://docs.gitlab.com/ee/api/users.html#for-admins.

You can lookup users by external UID and provider:

GET /users?extern_uid=1234567&provider=github

GetByPropertiesAsync("extern_uid=1234567&provider=github")

or

GetByPropertiesAsync(new GitLabApiClient.Models.Users.Requests.UpdateUserRequest() { ExternUid = "1234567", Provider = "github" })

The optional hard_delete parameter has been added to the Delete User function (https://docs.gitlab.com/ee/api/users.html#user-deletion).