[TRANSUP] nl by Richard

Signed-off-by: Werner Macho <werner.macho@gmail.com>
Fix #8174 (overlaps when using 'avoid intersections' functionality) + test

I am not entirely confident if it will work perfectly with older versions of GEOS (< 3.3)
because of the lack of unary union (that is emulated by series of unions of two geometries)
Fix #9396 (deactivate datum transform dialog by default)

Added a checkbox in Options > CRS > Default datum transformations to re-enable the dialog when desired
[composer] Keep relative position of items when pasting (fix #8598)
[composer] Fix item selection after pasting items
Fix #8864 (Random selection with subsampling broken)