Standardize the database upgrade mechanism
This patch is aim to standardize the upgrade mechanism which is currently in the method DatabaseInterface::initDatabase.
The idea is to avoid taking care about the upgrade logic when creating new versions.
On a new version XX, the steps would be the following:
1-create the method DatabaseInterface::upgradeDatabaseVXX 2-add the version to the enum DatabaseInterface::DatabaseVersion 3-add upgradeDatabaseVXX to the switch-cas in callUpgradeFunctionForVersion
Added mechanism for upgrade the database
Add integration for versions V9 -> V14
Added drop request for the unused tables
Reviewers: Elisa, mgallien, ngraham, astippich
Reviewed By: Elisa, mgallien
Differential Revision: https://phabricator.kde.org/D24563