Add --config argument to CLI

[DavisVaughan]

Consider the ruff/cargo approach of --config for overriding configuration settings rather than shoving them all in the command line api.

Their thought process is that you should not be setting things like --indent-width at the cli most of the time, that prevents you and your colleagues from having identical formatting experiences. Instead you should rely on the presence of an air.toml to hold the configuration details. But sometimes it is still useful to override this.

https://docs.astral.sh/ruff/configuration/#the-config-cli-flag