Remove client_url property for instance entity

...pp/admin/components/instance/instance-card.component.html

...pp/admin/components/instance/instance-form.component.html

.../app/admin/components/instance/instance-form.component.ts

client/src/app/metamodel/models/instance.model.ts

conf-dev/create-db.sh

server/doctrine-proxy/__CG__AppEntityInstance.php

server/src/Action/InstanceAction.php

server/src/Action/InstanceListAction.php

server/src/Entity/Instance.php

server/tests/Action/InstanceActionTest.php

server/tests/Action/InstanceListActionTest.php