Update robots.txt.ejs

Fix for issue DSpace#2709

Author: bram-atmire

src/robots.txt.ejs

@@ -16,6 +16,8 @@ Disallow: /submit
 Disallow: /workspaceitems
 Disallow: /profile
 Disallow: /workflowitems
+# Crawlers should be able to access entity pages, but not the facet search links present on entity pages
+Disallow: /entities/*?f
 
 # Optionally uncomment the following line ONLY if sitemaps are working
 # and you have verified that your site is being indexed correctly.