Description of the Change

As a developer
I want to see deployment status when calling cf app myapp
So that I can easily tell if that app is currently being deployed to, and what the status is.

Scenario: A PAUSED Canary Deployment
Given An app has an active/paused Deployment
When I call cf app myapp
Then I see the following line in the CLI output:

Canary Deployment currently PAUSED (since [[insert timestamp]])

Please run `cf continue-deployment myapp` to promote the canary deployment, or `cf cancel-deployment myapp` to rollback to the previous version.

Scenario: A DEPLOYING Canary Deployment
Given An app has an active/deploying Deployment
When I call cf app myapp
Then I see the following line in the CLI output:

Canary Deployment currently DEPLOYING (since [[insert timestamp]])

Scenario: A CANCELING Canary Deployment
Given An app has an active/canceling Deployment
When I call cf app myapp
Then I see the following line in the CLI output:

Canary Deployment currently CANCELING (since [[insert timestamp]])

Scenario: No Current Deployment
Given An app has no ACTIVE Deployments
When I call cf app myapp
Then I see no line about Deployments in the output

CC @a-b