Add hook for defining logging tables

By default when logging is turned on a bunch of tables are created to mimic the live tables. These tables are created as archive tables because of the perceived benefit of faster write speed.

OTOH archive tables cannot be indexed, are slower to retrieve information from and perform poorly when a join is done on them (due to the lack of indexing). Our current change log does not take this into account and does a join - which is slow. They can also not be subjected to purging old data

Over time we have experimented with changing them to INNODB and indexing them - this has been fine for us - although we've done it in a limited way - as has Brian.

This ticket proposes a hook to formalise that option - sample code is here

https://github.com/eileenmcnaughton/civicrm-core/commit/5f64659dc5e1e6bed7fd026d5b585117ae9b7e6f