So far ODIN standalone (-DODIN_WITHOUT_GAUDI) has been included in Allen, but grabbing ODIN.cpp from the LHCb master branch has maintenance issues. This came up in !4192 (merged) and is tracked in Allen#449 (closed).
The initial proposal was to remove the inheritance of ODIN from DataObject, but that would be quite invasive and would e.g. break exisiting GaudiPython scripts.
This MR provides an alternative by including a build of ODIN standalone into DAQEventLib. Removing inheritance from DataObject from ODIN can still be done later.
