Updated RateReview schema updated to include username column

[Bob]

I've updated the xf_nflj_showcase_rate_review table by adding a new column to store 'username' data. This deviates from the XFRM schema (it does not have a username column in the xf_resource_rating table, it relies on joins with the xf_user table). XFMG however, does store the username in its rating table so there is still standardization happening in that sense. Also, all other similar content types normally store username data with the record, so this isn't something new (its done with comments, replies, posts, etc).

The UPGRADE will fire a deferred process that will handle the updating of username data for the new column.

I've also added a new Showcase Rebuild for rebuilding Ratings and Reviews. This rebuild uses the same deferred process as used during the upgrade.

NOTE: This has already been updated in AMS, RMS and UBS.