Implement DuckDuckGo-like ! (or \\) syntax for IFL

Instead of having to pass lucky=1 as a GET parameter you can now enter
a search term beginning with "!" or "\" to have MetaCPAN return the
first result to you.

E.g. searching for "!Plack" or "\Plack" will redirect you to
/module/Plack.

This is an alternative to pressing Shift+Enter on the site to go to
the first result, but the real value is being able to use
e.g. DuckDuckGo to search for "!cpan !Plack" to go to the first
MetaCPAN result.

See-Also: https://github.com/CPAN-API/metacpan-web/pull/269
Add link to the module or distribution we are looking up the reverse dependencies for
Add another repo to include in the contributors page
Link to Perl.org - fix #454
Add canonical urls to help with SEO
Add meta description to modules and releases from the abstract
Get coderwall endorsement badge over https

closes gh-855.
Merge pull request #270 from CPAN-API/avar/ddg-bang-syntax

Implement DuckDuckGo-like ! (or \\) syntax for IFL
Merge remote-tracking branch 'upstream/master'