[Website]: Redirect old DataFusion CLI URL (#507)

Closes apache/datafusion#10124

# Rationale
See apache/datafusion#10124 -- basically we
moved a URL that is bookmarked / comes up in google search. We need to
redirect to the new location

# Changes
Use the `.htaccess` process added in
#505
#506 with @kou to redirect to
the new location

Author: alamb

.htaccess

@@ -15,3 +15,6 @@
 
 # redirect all datafusion URLs to new top level website
 Redirect permanent /datafusion https://datafusion.apache.org
+
+# redirect old URL https://github.com/apache/datafusion/issues/10124
+Redirect permanent /datafusion/user-guide/cli.html https://datafusion.apache.org/user-guide/cli/index.html