remove field guide cruft and update all field guide links to wiki

server/views/partials/challenge-modals.jade

@@ -6,7 +6,7 @@
             .modal-body.text-center
                 h3 This will take you to our pair programming room where you can request a pair.
                 h3 You'll need  
-                    a(href='/field-guide/how-do-i-install-screenhero' target='_blank') Screenhero
+                    a(href='//github.com/FreeCodeCamp/freecodecamp/wiki/How-to-install-Screenhero' target='_blank') Screenhero
                     | .
                 h3 Other campers may then message you about pair programming.
                 a.btn.btn-lg.btn-primary.btn-block(href='https://gitter.im/FreeCodeCamp/LetsPair', data-dismiss='modal', aria-hidden='true' target='_blank') Take me to the pair programming room
@@ -30,7 +30,7 @@
                 a.close.closing-x(href='#', data-dismiss='modal', aria-hidden='true') ×
             .modal-body.text-center
                 h3 Remember to use  
-                    a(href='/field-guide/how-do-i-get-help-when-i-get-stuck' target='_blank') RSAP
+                    a(href='//github.com/FreeCodeCamp/freecodecamp/wiki/How-to-get-help-when-you-get-stuck' target='_blank') RSAP
                     | .
                 h3 If you've already read the errors and searched Google, you should ask for help.
                 h3 This will take you to our help room.

server/views/resources/sitemap.jade

@@ -26,7 +26,7 @@ urlset(xmlns="http://www.sitemaps.org/schemas/sitemap/0.9")
     priority= 0.9
 
   url
-    loc http://www.freecodecamp.com/twitch
+    loc http://www.freecodecamp.com/coding-bootcamp-cost-calculator
     changefreq weekly
     lastmod= now
     priority= 0.9
@@ -59,10 +59,3 @@ urlset(xmlns="http://www.sitemaps.org/schemas/sitemap/0.9")
       lastmod= now
       changefreq daily
       priority= 0.9
-
-  each fieldGuide in fieldGuides
-    url
-      loc #{appUrl}/field-guide/#{fieldGuide.replace(/\s/g, '-')}
-      lastmod= now
-      changefreq daily
-      priority= 0.9