Default host for automated cbcollect

When selecting "upload to couchbase" under the collect logs feature, the host should be defaulted (but still editable) in our Enterprise edition. Otherwise the only place this is documented is the "working with support" wiki page so they would need to remember that URL in order to lookup the right URL they need to supply. We can trivially save them this inconvenience and default it to

s3.amazonaws.com/cb-customers OR cb-customers.s3.amazonaws.com