Separate config types into a look-up table and constrain cfg_config's config_type field to only accept one of those
values. This is just a create script for postgresql right now - will need migrate and create scripts for other DBs once
fully tested.
Update SelectTypes query to fetch types from the new cfg_type table, in order to improve the performance of this
frequent query. New InsertType and SelectTypeWhere elsql macros are defined for checking if a particular config
type exists, and to insert a new config type in the cfg_type table. The insert() method in DbConfigWorker now
automatically adds any previously unseen config type to the cfg_type table, so the behaviour is still largely the
same as before.
Create & migrate scripts for version 47 of the config db. These create a cfg_type table, constrains cfg_config's
config_type field to use a type name specified in cfg_type, and populates the newly created cfg_type table with
distinct config type names from cfg_config.
Remove 'WITHOUT oids' from hsql and sqlserver2008 config db upgrade scripts