Open IMCE in modal dialog

Drupal 8 has a shiny new modal dialog API in core (see views usage of new modal API). It would be great if IMCE opened in a modal as it provides a better user experience and consistent presentation. With IMCE opening in a new window as it does now, ugly window frame, title and URL are visible. Also, sometimes an IMCE window is launched but the user navigates away from the calling window, switches windows/tabs or focusses on another application and the zombie IMCE window is left in the background. IMCE would be better suited to a modal.

Related issues:
#3129335: Create a new submodule to allow use IMCE in modal ui