quickstart: wait for psql to start & expose argo ui

[szab100]

1. On slower k8s clusters, waiting until the postgresql pod becomes ready is not enough, we need to wait until it can serve requests instead, otherwise db creation and the db_migration job fails.
2. Expose the Argo (web) UI on http://localhost:2746/ (with no authentication required) for better observability of cello workflows.

[codecov-commenter]

Codecov Report

Merging #345 (e799d12) into main (5de3347) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

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  Coverage   69.63%   69.63%           
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  Files          11       11           
  Lines        2052     2052           
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  Hits         1429     1429           
  Misses        521      521           
  Partials      102      102           

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[szab100]

@grantleehoffman @jk-intuit Can we create a build job (or extend the current one) that builds these two docker images {cello, cello-db-migration} and pushes them to ghcr.io with version + latest tags and set the imagePullPolicy to Always in the manifests? So that the quickstart stack can start up quicker, become more stable and drop the docker requirement?

[szab100]

note: a better solution for this would be to add proper readiness/liveness probes to the postgres deployment