Modify pubsub tables so that all supported databases may correctly run the database scripts
The pubsubNode table is holding some n relationships by encoding strings in big fields. This is generating some problems in old versions of MySQL or hitting some limits of SqlServer. We can move the n relationships (e.g. contacts, roster groups, reply rooms, etc.) to a new table thus reducing the size of pubsubNode. Also make sure that primary keys and indexes are not reaching any db limit.