Add simple function for uploading OFX-based transactions

The OFX direct connection for my bank isn't working right now. I have a
support ticket in. Until then I'm going to work on doing a manual upload
and parse of transactions from this OFX document

templates/account.html

@@ -29,4 +29,10 @@
 {% else %}
   <p>This account does not have any transactions yet</p>
 {% endif %}
+<form method="POST" action="/transactions/" enctype="multipart/form-data">
+  <p>Want to upload your own transactions? Cool. Do it here.</p>
+  <input type="hidden" name="account_uuid" value="{{ account.uuid }}">
+  <input type="file" name="transactions" id="transactions">
+  <input type="submit">
+</form>
 {% endblock %}