Persist install selection

:fork_and_knife: 

When a signed in user clicks the install instructions for a cookbook, persist their selection on their account.

todo:

- [ ] update the installs view to be less nutso
- [x] get the feature spec passing

Trello card: https://trello.com/c/l7YoGfzK
@tristanoneil after implementing this, it ended up adding a bunch of more logic and conditions to the `cookbooks/_installs` partial. I am wondering whether or not it is worth it? What do you think?