Customize Auto DevOps deployment target
### Problem to solve
Auto DevOps only provides Kubernetes as its deployment target. Users who use different infrastructure (AWS, rsync, fargate) cannot take advantage of Auto DevOps out of the box.
### Further details
<!-- Include use cases, benefits, and/or goals (contributes to our vision?) -->
### Proposal
1. Provide a common `deploy` command for all deploy-related Auto DevOps jobs (staging, production, canary, incremental rollouts).
1. Allow customization of the target for the `deploy` command, ie k8s, ec2, etc.
### What does success look like, and how can we measure that?
<!-- Define both the success metrics and acceptance criteria. Note that success metrics indicate the desired business outcomes, while acceptance criteria indicate when the solution is working correctly. If there is no way to measure success, link to an issue that will implement a way to measure this. -->
### Links / references
https://gitlab.com/gitlab-org/gitlab-ce/issues/47234#note_147629654
https://gitlab.zendesk.com/agent/tickets/83051
<details><summary>Original issue content</summary>
<p>
https://gitlab.zendesk.com/agent/tickets/83051
### Description
I saw the release of Gitlab 10.0 and was very pleased with all the new functionality! I noticed that the deployment features [for Auto DevOps] only support Kubernetes. We primarily deploy to AWS ECS so I would like to "vote" for requesting ECS deployments.
### Feature checklist
Make sure these are completed before closing the issue,
with a link to the relevant commit.
- [ ] [Feature assurance](https://about.gitlab.com/handbook/product/#feature-assurance)
- [ ] Documentation
- [ ] Added to [features.yml](https://gitlab.com/gitlab-com/www-gitlab-com/blob/master/data/features.yml)
/cc @bikebilly
</p>
</details>
issue