Works much the same as intersect operator,
expose as a new operator since for users its quite different.
Access from face menu.
Internally, this adds boolean args to BM_mesh_intersect function.
Was the case of several Mesh operators actually (and probably others, but cannot check
everything). Added `RNA_def_property_float_distance` helper, avoids having to
set PROP_DISTANCE subtype explicitly each time...
Modeling tool to cut intersections into geometry (like boolean, without calculating inside/outside).
Faces are split along intersections, leaving new edges selected.
Access from Face menu.
