Remove recursive redirect, add /saas redirect (#509)

Author: zach-carr

config/redirects

@@ -1,7 +1,7 @@
 define: base https://docs.mongodb.com/charts
 define: versions 19.12 master
 
-raw: charts/index.html -> ${base}/
 raw: charts/master/ -> ${base}/
+raw: charts/saas/ -> ${base}/
 
 [19.12]: charts/${version}/ -> ${base}/