Addon upgrades

Soffid addons should be able to manage data schema changes. Soffid gives addons a standard procedure to perform data and schema upgrades. The data upgrade process is performed in three steps:

1. The addons to upgrade are deployed into the soffid console using the Plugins screen.
2. On console boot, the data schema is updated. To perform the schema update, a Soffid developed schema updater is used. This schema updater will read the core-ddl.xml and any plugin-ddl.xml file to upgrade at once the core Soffid database objects as well as any addon database object. (See Data schema descriptor)
3. The application bootstrap process is executed. At this step, any spring bean implementing ApplicationBootService will be invoked. This been is responsible for completing data upgrade. Addons can also define a bean implementing ApplicationBootService for this purpose.