Clean up defunct upload and CRL logic.

- Applies our previous CSP namespacing pattern to the upload classes.
- Removes code and config for previous uploader implementation.
- Removes Attachment model's ability to upload files directly and
  adjusts tests that expected that behavior.

atst/routes/task_orders/new.py

@@ -17,7 +17,7 @@ from atst.utils.flash import formatted_flash as flash
 
 
 def render_task_orders_edit(template, portfolio_id=None, task_order_id=None, form=None):
-    (token, object_name) = current_app.uploader.get_token()
+    (token, object_name) = current_app.csp.files.get_token()
     render_args = {"token": token, "object_name": object_name}
 
     if task_order_id: