`dart create` should offer convenience `--project-name` like `flutter create`

[kriswuollett]

Use case is creating a Dart package in a monorepo where one doesn't need the full package name in the directory name, e.g., package company_division_api in directory ./company/division/api where monorepo pubspec_overrides.yaml are managed by ./melos.yaml.

Currently my workaround is:

$ cd company/division
$ dart create -t package company_division_api
$ mv company_division_api api

It would be nice to have:

$ dart create -t package company_division_api ./company/division/api