Better control of User Deletion in User Administration page

[kuchtiak-ufal]

Implement few improvements in Access Control - People page:

• add warning message in Delete Confirmation dialog when user is submitter for existing items:

Warning: User is submitter for existing items!

• disable or don't allow admin user to remove himself/herself
  (case when logged in admin user wants to remove himself/herself)

• add warning message in Delete Confirmation dialog when user is admin (warning when removing another admin):

Warning: User is admin!

In case of (1) user is submitter for existing items and (3) user is admin - add both warnings.

To check if user is submitter, use the following API requests:

// check archived items for the user
GET /server/api/discover/search/objects?page=0&size=1&query=submitter_authority:USER_ID

// check workspace items for the user
GET /server/api/submission/workspaceitems/search/findBySubmitter?uuid=USER_ID&size=1

// check workflow items for the user
GET /server/api/workflow/workflowitems/search/findBySubmitter?uuid=USER_ID&size=1

In all requests, check the totalElements value in the response.

See also: ufal/clarin-dspace#1345

[kuchtiak-ufal]

I've implemented change, on the backend, where the DELETE request
DELETE /server/api/eperson/epersons/USER_ID
returns 403 when admin is trying to delete himself/herself (see ufal/clarin-dspace#1349)

Now user gets the strange error message (in RED window), saying:

Successfully deleted EPerson: "{{name}}"

See:

[kuchtiak-ufal]

The fix for the issue is here:

git diff src/app/access-control/epeople-registry/epeople-registry.component.ts

diff --git a/src/app/access-control/epeople-registry/epeople-registry.component.ts b/src/app/access-control/epeople-registry/epeople-registry.component.ts
index 426de1bb8..76d8487bf 100644
--- a/src/app/access-control/epeople-registry/epeople-registry.component.ts
+++ b/src/app/access-control/epeople-registry/epeople-registry.component.ts
@@ -206,7 +206,7 @@ export class EPeopleRegistryComponent implements OnInit, OnDestroy {
               if (restResponse.hasSucceeded) {
                 this.notificationsService.success(this.translateService.get(this.labelPrefix + 'notification.deleted.success', {name: this.dsoNameService.getName(ePerson)}));
               } else {
-                this.notificationsService.error(this.translateService.get(this.labelPrefix + 'notification.deleted.success', { id: ePerson.id, statusCode: restResponse.statusCode, errorMessage: restResponse.errorMessage }));
+                this.notificationsService.error(this.translateService.get(this.labelPrefix + 'notification.deleted.failure', { id: ePerson.id, statusCode: restResponse.statusCode, restResponse }));
               }
             });
           }