Add print styles to improve smart answers printouts

• Remove any unwanted page elements (breadcrumb, change links etc)
• Remove link underlines for better clairty
• Limit page title width for better line length
• Remove margin for prev answers table and add cell padding
• Adjust prev answers table column widths for better readability
• Fix inconsistent alignment of '!' for help/info notices

https://www.agileplannerapp.com/boards/105200/cards/6344
These two selector groups could be combined into one `.smart_answer` scope, it's a bit easier to read and is a good habit to get in to.

(This isn't documented on the [styleguide](https://github.com/alphagov/styleguides/blob/master/css.md), but maybe it should be? CC @edds)