Improve db upgrade process
Improve the database upgrade process in the following ways:
Change version storage so that it stores a single version value instead of major and minor version. The schema version should be less linked to the Wildfire application version so that we can make multiple schema updates inside of a single app release.
The upgrade process should update the version number instead of having to do that in the upgrade scripts.
Use i18n strings instead of hard-coded english.
Make the version table capable of storing version information about plugin db schemas by including a "name" column. The name for the Wildfire db schema version will be "wildfire".