Allow overriding debian.yaml file path or arch property via CLI

[richnetdesign]

I have a Linux Flutter app being compiled for both AMD64 and ARM64

I've found the arch parameter to build allow choosing the build output to package.
flutter_to_debian build --arch arm64

However this arch parameter doesn't seem to override the arch in debian.yaml.
So I end up with arm64 executable in a debian package with a manifest stating it's arch in amd64 making it uninstallable.

There are several different ways this could be solved. I think a simple solution would just be to allow me to create a debian_arm64.yaml file, and then pass it as a parameter flutter_to_debian build --arch arm64 ./debian/debian_arm64.yaml