feat: opt out of multiple environments

[mtwichel]

Description As a developer, I often do not want to create an app with three separate environments, I just want a default main one (especially if I'm quickly prototyping an idea). However, I also love using the very_good create command to create a new project with very_good_analysis and bloc already baked in.

My current way to achieve this is to generate an app using flutter create, then delete a lot of things, add the dependencies, and copy an analysis_options.yaml file, but it would be nice to simplify that process a lot.

I imagine this syntax could be either:

• Add a flag that is something like --single-environment or --no-multi-environment
• Create a new template type - maybe -t single_env_app

This might take a lot of work (probably a new template behind the scenes) so I have no expectations, I just thought I'd give the feedback and see if it resonates with the VGV team :)

Thanks for everything you guys do! 💙