Fix bold styling on result count

After adding the reset to fix spacing issues, it also removed the
font-weight from `<strong>`. This commit styles the strong element with
the same font-weight as is coming from the govuk_template.
Fix rspec.rake so it doesn't fail

This project uses rspec-rails not rspec so the check for the rspec gem always failed. I've switched this code to try and then catch if the dependencies are not loaded. This approach has been used in specialist-frontend.
Merge pull request #37 from alphagov/fix-bold-on-results-count

Fix bold styling on result count
Merge pull request #39 from alphagov/fix-bundle-exec

Fix rspec.rake so it doesn't fail
Add no robots header AAIB Report urls

Before we do anything stop crawlers hitting aaib-reports urls, or anything else in our exclusion list for that matter!
Create AbstractDocument class from CmaCase class

As with the other apps lets abstract common document code into an AbstractDocument class to make it easier to inherit from this when creating other types of documents.
Allow the finder to deal with AaibReports

Instead of simply using the same presenter for all documents, we can switch based on the document_type attribute and use this to specify custom metadata attributes for document types we know about.
Make date labels visible on finder document listing

Previously we were hiding all labels with css. Instead lets add a special class for dates so we can target the label and display them to the user.
Use the correct noun depending on document_type

Instead of hardcoding the document_noun to cam cases use the document_noun from the schema
Use custom mappings for attribute names
Scope strong style to .result-info

In 90a8325b0ba3d0cfb91356fe19d81635c313869d I added a declaration for
strong which was global. Although this repo doesn't have govspeak, it
may have in future, so this commit scopes the declaration to the relevent
place.
Merge pull request #40 from alphagov/scope-strong-to-result-info

Scope strong style to .result-info
Move metadata formatting to helpers

Move document metadata formatting into helper methods and remove the complexity from the view.
Move time formatting to i18n
Merge pull request #38 from alphagov/feature/add-aaib-reports

Allow handling of AAIB Reports
Refactor AbstractDocument

Be more consistently functional throughout and make the label overrides
generic enough to handle any labels, not just date labels.

Also a little bit of code-style tidying (`%w` and whitespace).
Merge pull request #41 from alphagov/refactor-abstract-document

Refactor AbstractDocument