Adds crawler directives to result and record pages

Why are these changes being introduced:

* It doesn't make sense to have search engines index and follow links
  from our own results and record pages

Relevant ticket(s):

* https://mitlibraries.atlassian.net/browse/TIMX-476

How does this address that need:

* adds meta robots tag with noindex, nofollow rules

Author: JPrevost

app/views/record/view.html.erb

@@ -1,5 +1,9 @@
 <%= content_for(:title, record_page_title(@record)) %>
 
+<% content_for :additional_meta_tag do %>
+  <meta name="robots" content="noindex, nofollow" />
+<% end %>
+
 <%= render(partial: 'shared/error', collection: @errors) %>
 
 <%= render(partial: 'shared/site_title') %>

app/views/search/results.html.erb

@@ -1,5 +1,9 @@
 <%= content_for(:title, results_page_title(@enhanced_query)) %>
 
+<% content_for :additional_meta_tag do %>
+  <meta name="robots" content="noindex, nofollow" />
+<% end %>
+
 <div class="space-wrap">
 
   <%= render partial: "shared/site_title" %>