Add `notes` to the duplicated activity data.

[#56448800] https://www.pivotaltracker.com/story/show/56448800
Clarifying comment
Proposed fix for reordering bug [#62329238].

https://www.pivotaltracker.com/story/show/62329238
Merge branch 'refs/heads/multi-portal-auth'
Login path links to account picker
Reads portal configuration from YAML [#55550912].

This version is flat, to deliver just the name => url mapping. The next step will be to provide more data per configuration. Note that the keys are now strings, not symbols, throughout. (Also note that when we have more data, this YAML file will get moved into a "sample" and the real one will be deployed via Chef.)

https://www.pivotaltracker.com/story/show/55550912
More-structured portal configuration in YAML.

This allows stowing image URLs and portal client secrets along with the URLS, which will happen when we start publishing to these portals.
Use images in the auth selection page, if provided.