Introduce rest api to update speed limit value
Change speed limit update request type to PUT
Require user authorization in backend api when modifiying speed limit value
Provide current user username as a parameter to updateSpeedLimit function
Reactivate speed limit selection when speed limit is saved
Rollback changes if speed limit update fails
Merge pull request #293 from finnishtransportagency/add_speed_limit_update_api

Add speed limit update api