Add tool for managing projects

[subfuzion]

Initial concept: tool should support package API that can be used by both a CLI and Cloud Code for enhancing developer experience working with Functions Framework for Dart projects, making it easy to create, deploy, and monitor function apps.

• [ ] Including project scaffolding support; generate example and starter projects (relates to #19 - one or more starter project templates can also be exposed through stagehand)
• [ ] Minimize need for installing other tools (gcloud, stagehand, etc) to work with cloud projects
• [ ] Associate current project with a Google Cloud project, deploy, get URL, open logs/traces directly
• [ ] Potentially be able to add new handlers (and tests) for different HTTP methods and Cloud Event types to an existing project.

[subfuzion]

Rationale for project support:

Currently, we require that you install and configure gcloud (see the repo docs). We can make this step easier for users who aren't familiar with the Google Cloud SDK, while still respecting the gcloud configuration, if there is one.

For example, a deploy command might accepts a --project ID argument, but if not supplied, also checks the active gcloud configuration and possibly a project-local configuration, for example:

.function.yaml

project: demo-project
region: us-central1
runtime: cloudrun  # or gcf