MXGDA-870 EPICS: Suppress type mismatch warnings from LazyPVs when using newBooleanFromEnumPV or newReadOnlyBooleanFromEnumPV

(cherry pick of cc945d3 from master branch)
MXGDA-870 EPICS: Add newIntegerFromEnumPV factory method to LazyPVFactory

(Type mismatch warnings are suppressed when creating a LazyPV in this way.)

(cherry pick of 719cb98 from master branch)
Handle the opening of a fast shutter as part of triggering the PCO
camera
EpicsScannable notify observers of change with a
ScannablePositionChangeEvent
Merge remote-tracking branch 'origin/8.28'