Updates to the database structure

Requests to update the database. Each database contains within it a table with settings where the version of the last applied update file is located.

Each update file has a name beginning with a number representing the date, in the format of YYMMDD_*.sql. Whenever the corresponding role is reloaded, those update files that represent later versions relative to the current database version are applied. And their application goes in the order of increasing version of updates.

Updates to the working domain entity database are applied simultaneously to all working domain databases and to the template database from which the databases for newly created domains are deployed.