mapstore: strategy RollingUpdate improvements

[edevosc2c]

Currently, mapstore is in strategy Recreate because by default mapstore may automatically update the database schema. Recreate avoids having an old mapstore that is using the old db schema while a new one is updating the schema, essentially avoiding any potential SQL conflicts.

But you can ask mapstore to not update the schema automatically: validate: validate the schema, makes no changes to the database.. This would allow the administrator to set mapstore to RollingUpdate because it would be safe from unwanted SQL changes.

The goal of this issue is to offer the ability to:

• modify geostoreEntityManagerFactory.jpaPropertyMap[hibernate.hbm2ddl.auto] in order to allow the admin to set to validate
• and allow the ability to set the mapstore deployment to RollingUpdate