Cancel deployment from CLI

Is your feature request related to a problem? Please describe.

For some of our projects, we need to set some environment variables at environment level before the first deployment. Creating an environment without starting a deployment currently is not possible.

If we are able to cancel a deployment, we could start a deployment and directly cancel the deployment to create an environment in lagoon without actually deploying it. This allows us to set the correct environment variables (via CI / CLI) and then start a new correct deployment

Describe the solution you'd like

1. Be able to create an environment without directly deploying to it, to be able to set environment variables for the environment
2. Cancel a deployment by its identifier

Describe alternatives you've considered

1. Start the new environment with a deployment and directly cancel the deployment
2. Set the environment specific variables as environment variables at project level and remove after the environment has been created
3. Start a build using lagoon deploy branch --project {PROJECT} --branch {ENVIRONMENT_NAME} --branch-ref NONEXISTENTHASH if the environment does not exist, so the first build will fail at stage Checkout Repository

Additional context
N/A

Start at the CLI's lagoon deploy branch command and trace how it creates deployments and handles deployment identifiers. Done means the CLI can cancel a deployment by identifier and support creating an environment without completing its initial deployment, covering both requested workflows.