DOP-2117: Specify carousel Card layout (#70)

Author: mango-db

source/index.txt

@@ -16,6 +16,7 @@ Welcome to the MongoDB Documentation
 
 .. card-group::
    :columns: 3
+   :layout: carousel
 
    .. card::
       :headline: Run a self-managed database
@@ -103,6 +104,7 @@ Community.
 
 .. card-group::
    :columns: 2
+   :layout: carousel
 
    .. card::
       :headline: Free Online Courses on MongoDB University