Move webui from /loop/webui to /webui

Thanks, perl (and git mv):

	perl -pi -e s,loop/webui,webui,g $(git grep -l loop/webui)
diff --git a/dockerimg/dockerimg.go b/dockerimg/dockerimg.go
index c97c989..b5e6188 100644
--- a/dockerimg/dockerimg.go
+++ b/dockerimg/dockerimg.go
@@ -22,7 +22,7 @@
 	"time"
 
 	"sketch.dev/loop/server"
-	"sketch.dev/loop/webui"
+	"sketch.dev/webui"
 	"sketch.dev/skribe"
 )