Revert "installed Zero, One, and MinusOne for IsHomalgLibSingularRingRep"

This reverts commit b2db570541088fe7e2f4644a8313c9baa994c7e3.

(needs libsing 0.4: thanks Max N. & Max H. & Frank & Hans)
remove homalgIOMode( "D" ) and SetAssertionLevel( 6 ) from ReducedBasisOfModule.g