As notified in the 4.14.0.0 release notes, this deprecates the legacy UI
and moves it under the ui/legacy directory which will be served at
/client/legacy URL path. This will also ensure that users upgrading or
installing 4.15.0.0 will get the new UI by default. This will also make
it simpler to remove the old UI for future 4.16/master releases.
Co-authored-by: Daan Hoogland <daan.hoogland@shapeblue.com>
