make ui configurations selectable (closes #2406609)
* introduce a new 'uicfg' registry (storing instances)
* use the relevant new APIs from lgc.registry to manage the new
registrable uicfg objects
* cw event manager useage is gone; instead thze standard registry
reloading mechanism is used
* ensure i18n commands still work (devctl)
* introduce dynamic uicfgs use whenever possible (various views), even
though sometimes the classic 'static' usage remains