Configure Rubocop

Make Rubocop less strict about arrays in spec/, because
%w doesn't always make for the clearest test data.

The default configuration dislikes inject and recommends
each_with_object, but I disagree.
Add a tabular review aggregator

This aggregates reviews in a suitable format for CSV generation.
Implement a CSV renderer for a user's reviews

This takes the user and a tabular aggregator and combines the
information into a CSV file with keywords translated via the locale
file.
Allow user to download their feedback as CSV

And, by extension, to allow a manager to download a direct report's
feedback as a CSV.
Download all direct reports' reviews as CSV
Remove unused ivar
Distinguish link text for CSV download all vs one
Test all CSV downloading scenarios
Linking to an alternative format is easy

We only need to specify the link parameters we're changing.
Merge pull request #4 from ministryofjustice/csv-exports

CSV exports
Update invitation email copy, add closing date
Update default invitation message
Go directly to editing feedback after accepting
Small update to feedback request email copy
Simpler copy for number of feedback requests
Simpler copy for number of requests sent
Fix degree symbol
Don't show the h1 if we have nothing to say

We no longer show 'SCS 360° Appraisals' as an h1 where we have nothing
better to add - this is shown in the page header in any case.

I have a nagging feeling that we ought to be able to clean up and
simplify the navigation and headers, because it's feeling increasingly
special-cased and hacky.
Show introductory text in place of page title
Embolden text in intro