Admin panel: "Confirm remove" messages

In the admin panel, upon removal of users or maps there should be "Confirm remove" messages, saying "Are you sure to delete/remove project/user ?"

created branch 316-admin-panel-confirm-remove-messages

mentioned in merge request !233 (merged)

closed via commit 0d589d4f

closed via merge request !233 (merged)

mentioned in commit 0d589d4f