Use HTML beautifier to indent ERB files

We had inconsistent indentation in many places. Now we're fixing them
and adding a linter to our CI so we don't accidentally introduce
inconsistent indentations again.

app/components/admin/stats/stat_component.html.erb

@@ -1,5 +1,6 @@
 <div class="small-12 medium-4 column">
   <%= tag.p(**options) do %>
-    <%= text %> <br><span class="number"><%= amount %></span>
+    <%= text %> <br>
+    <span class="number"><%= amount %></span>
   <% end %>
 </div>