gitignore the files generated while building the debian package (#1059)

debian/.gitignore

@@ -0,0 +1,7 @@
+# Generated during the build
+/crowdsec
+/files
+/*.substvars
+/*.log
+/*.debhelper
+/*-stamp

debian/debhelper-build-stamp

@@ -1 +0,0 @@
-crowdsec