allow streaming downloads to export channel feed data

app/views/channels/_import.html.erb

@@ -1,4 +1,5 @@
 <div class="FL">
+  <h3><%= t(:import) %></h3>
   <%= t(:upload_select) %>
   <br>
 
@@ -11,6 +12,12 @@
     <%= f.submit t(:upload), :disable_with => t(:uploading) %>
   <% end %>
 
+  <br><br>
+
+  <h3><%= t(:export) %></h3>
+  <%= t(:download_feeds) %>
+  <br><br>
+  <%= button_to t(:download), "#{@ssl_api_domain}stream/channels/#{@channel.id}/feeds?api_key=#{@channel.write_api_key}" %>
 </div>
 
 <div id="sidebar_old" >