Add SQLite database support

Parent: [EPIC] AURA Docker Compose Integration Test Suite (aura-tests#5)

It’d be really nice to have SQLite support in tank including support in the (docker) container image so that tank can be used without a separate database service.

This would be very helpful for automated tests in the dashboard, because adding a PostgreSQL service would make the gitlab-ci config in the dashboard very complex (gitlab ci services cannot easily depend on on each other), unnecessarily increases load on the CI runners and therefore affects test performance and makes the test setup more brittle. It would also greatly simplify the current test-scheme job implementation.

Dependency

To support SQLite in Tank we first need to Upgrade to GORM 2 and gormigrate v2 (#36 - closed). Both is required to continue with the parent epic aura-tests#5.