Add zenml stack recipe CLI commands

[wjayesh]

Describe changes

Stack Recipes CLI commands

This PR introduces the zenml stack recipe CLI commands that allow the following functionalities.

• zenml stack recipe list: List all available stack recipes.
• zenml stack recipe pull <recipe-name>: Pull a recipe to your local filesystem.
• zenml stack recipe deploy <recipe-name>: Deploy a specific stack recipe and auto-import the resources created, as a ZenML stack.
• zenml stack recipe destroy <recipe-name>: Destroy all resources created by a recipe.
• zenml stack recipe clean: Deletes the pulled recipes from the local filesystem.

Extensive error messages are put in place to guide users if the commands fail. This has been done keeping in mind that the feature would be in alpha, and things could break unexpectedly.

Terraform wrapper

A Terraform class is implemented as a wrapper around the terraform CLI. It adds the following features:

• Check if the user has terraform installed. Raise an exception and point them to the installation page if they don't have it.
• Implement an apply command that performs a terraform init and then terraform apply on the recipe. The init is only performed once to save time.
• A destroy command that performs a simple terraform destroy but can potentially include a --force parameter in the future to force deletion of resources. Keeping it out for now, in the absence of tests, to avoid unintended consequences.
• Option to set log level for the terraform command executions.

Features yet to be added:

• Ability to run these commands in the background using the ZenML service concept.
• Check user credentials to verify if they have permission to execute the recipe.

Minor changes

• While importing a stack, there's now an option to force-import a YAML configuration with a different version than the current ZenML version.

Pre-requisites

Please ensure you have done the following:

• I have read the CONTRIBUTING.md document.
• If my change requires a change to docs, I have updated the documentation accordingly.
• If I have added an integration, I have updated the integrations table and the corresponding website section.
• I have added tests to cover my changes.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Other (add details above)

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[AlexejPenner]

Beautifully done, love all the usability goodies and clear error/warning messages 🔥