QAFE-983 As QAFE developer I want to execute an event with "log"
built-in on the client-side when a button is clicked so that I can
execute "log" without server-side round-trip.
- Added LogHandler for handing client-side events
- Added LogAssembler for sending server-side components to client-side
- AbstractBuiltInHandler now contains getUUId-function to reuse for
other client-side built-ins.