* NEW DatabaselessKernel to support operation without DB
This is required for GraphQL code generation in CI (without a working runtime database/webserver environment).
Context: https://github.com/silverstripe/silverstripe-graphql/issues/388
* New --no-database option for sake
* Refactor to abstract class
* Apply feedback peer review
Co-authored-by: Aaron Carlino <unclecheese@leftandmain.com>
Co-authored-by: Maxime Rainville <maxime@silverstripe.com>