First modularity merge to trunk

I have merged the first part of modularity project into trunk. This does no add any new functionality, it just contains the new database infrastructure to manage modules which includes a table (AD_Module) to maintain the installed modules in the instance and a reference to this table in many application dictionary tables (you can see the complete list of the affected tables here).

The purpose of this early merge is to try to affect other projects for r2.50 as llittle as possible but, in any case, it would be advisable to synchronize these projects with trunk as soon as possible in order to minimize the risk of conflicts.