A bunch of tweaks to the Users directory

- Move user directory from `/directory` to `/users/`
- Defaults to 'weekly' time period
- Don't include deleted topics/posts in the results
- Move heart icon to header instead of on each row
- "Users" instead of "Users found"

test/javascripts/integration/users-test.js.es6

@@ -0,0 +1,8 @@
+integration("User Directory");
+
+test("Visit Page", function() {
+  visit("/users");
+  andThen(() => {
+    ok(exists('.directory table tr'), "has a list of users");
+  });
+});