Move getUserPowerLevel to modelService.

syweb/webclient/components/matrix/event-handler-service.js

syweb/webclient/components/matrix/model-service.js

syweb/webclient/room/room-controller.js

syweb/webclient/test/unit/event-handler-service.spec.js

syweb/webclient/test/unit/model-service.spec.js