Revert "Temporarily add a local relative part to register ui components"

This reverts commit 7743b0e9cf848d43e4a15d309e3b6df2dc377e3f.
Make openproject-ui_components a GitHub dependency

openproject-ui_components is pending publishing as a Bower
component (Task #5144)

Signed-off-by: Alex Coles <alex@alexbcoles.com>