remember layers selection between user sessions

remember the user's selection of active layers between browser sessions.

[x] the solution must use the simple module already present in the application, defined here: https://github.com/openmove/odh-mentor-otp/blob/master/journey/app/lib/otp-ui/core-utils/storage.js
[x] the solution must remember the selection of both baselayers(openstreetmap,print..) and overlay layers(bikesharing,echarger ecc)
[x] it must remain important to be able to add new overlays, configuration baselayers, in addition to those already present.
[x] important that a layer selected when the browser is closed is loaded immediately when the browser is opened next times

openmove / odh-mentor-otp