Autodetect dialect based on configured driver

Most drizzle-kit commands require explicitly passing the dialect after a colon. However, for a configured database connection this dialect can already be inferred based on the selected driver (e.g. `driver: "better-sqlite"` corresponds to `foobar:sqlite`).

This would make the commands easier to use, especially when dealing with different databases between projects which currently means that one has to always look up which database is used to select the correct command.