Ignore all build artifacts

Instead of listing .o etc. files by name, match them using wildcards.

Signed-off-by: Stephen Kitt <steve@sk2.org>

software/.gitignore

@@ -1,9 +1,4 @@
 infnoise
-KeccakF-1600-reference.o
+*.a
-daemon.o
+*.o
-healthcheck.o
+*.so
-infnoise
-infnoise.o
-libinfnoise.a
-libinfnoise.o
-libinfnoise.so