Mark plugins as legacy-incompatible

Performed using the shell commands:

sed -i '' -e \
'/^@Plugin/,/^public class/s/)$/, attrs = { @Attr(name = "no-legacy") }&/' \
-e 's/import org.scijava.plugin.Menu;/import org.scijava.plugin.Attr;\
&/' $LIST

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>