Uffizzi Opensource compose ECR support

[zipofar]

We need to move all changes from #1282 (closed) into the open-sourced app

[NealArw]

TESTED on prod - OK

# uffizzi connect ecr
Registry Domain:  https://***
Access key ID:  ***
Secret access key:
Successfully connected to ECR
# vi compose-ecr.yml
# uffizzi preview create -o=json compose-ecr.yml
[✔] Creating containers...
[✔] Deploying preview...
  [✔] webhooks-test-app
{"id":"deployment-5","url":"https://deployment-5.default.app.qa-gke.uffizzi.com"}
#