Modernize LoKi

• prefer Gaudi::Functional
• prefer DataObjectReadHandle
• prefer Gaudi::Property
• prefer monadic StatusCode functions

added backport run2 modernisation labels

/ci -test --merge

/ci-test --merge

assigned to @mstahl

resolved all threads

added lhcb-gaudi-head label

added 1 deleted label and removed lhcb-gaudi-head label

approved this merge request

assigned to @rmatev and unassigned @mstahl

mentioned in merge request !2290 (merged)

removed 1 deleted label

mentioned in issue Moore#128 (closed)

@rmatev @graven what is the status here? I see that @mstahl said this was ready to merge a couple of weeks ago.

mentioned in issue Moore#131 (closed)

added lhcb-gaudi-head label

mentioned in merge request !2298 (merged)

Nightlies happy so I think this is ready to merge @rmatev.

removed lhcb-gaudi-head label

resolved all threads

mentioned in issue Moore#136 (closed)