Implement an Azure Functions for Rust SDK.

[peterhuene]

Is your feature request related to a problem? Please describe.
Currently, users have to manually set up their Rust project to use Azure Functions for Rust. Additionally, there's a lot of hoops to jump through to test their functions locally or deploy to Azure.

Describe the solution you'd like
I would like to see an easy-to-install "Azure Functions for Rust SDK".

Users would be able to install via cargo install azure-functions-sdk (implemented in #45).

The SDK will have a dependency on having a version of Docker 18.06 or higher installed.

Likely commands:

• cargo func new-app - Create a new Azure Functions for Rust application (implemented in Implement the Azure Functions for Rust SDK (Part 1). #45).
• cargo func new - Add a new Azure Function to the application from a list of templates (implemented in Implement the cargo func new command. #145).
• cargo func run - Builds and runs the Azure Functions application locally using the Azure Functions Core Tools (implemented in Implement cargo func run. #89).
• cargo func deploy - Builds the Docker image for the Azure Functions for Rust application and then deploys it to Docker Hub (repository should be configurable). Possible integration with the Azure CLI tools for management of Azure resources.

Describe alternatives you've considered
N/A

Additional context
N/A