Migrate deployment from Travis to Actions

[kcranston]

Steps for migration:

• Create gcloud service account for actions
• Setup CGloud
• workflow for building and pushing docker images, see template for docker build + push
• workflow for deploying new clusters (helm updates), see template for GKE deployments
• change the way we do deployment secrets by adding them to the repo under Settings rather than storing them as code in the repo; see https://docs.github.com/en/free-pro-team@latest/actions/reference/encrypted-secrets
• disable travis gcloud service account

@mbjoseph has given us a good first step by translating our travis file to Actions in his fork. We probably want to aim for re-writing the whole workflow in Actions (i.e. use as much of the Actions tooling as possible, rather than just calling deploy.py script in an Actions workflow and having it do most of the work).

[lwasser]

@kcranston i've been adding secrets to the repos to support actions. let me know what you need as it's super easy to do. i'm really loving actions a lot

[lwasser]

the one consideration is that if deploy.py works, it could be run on any CI infrastructure so the question is - are we sure we want to stick with actions for a while or is flexibilty nice. i also run deploy locally and it seems to work when i'm in a pinch - ci not working.

[kcranston]

Good point, @lwasser We will need to make changes to deploy.py to remove the travis bits, so this might be a good time to add a --local option for running locally using local gcloud credentials.

[lwasser]

@kcranston i think we can close this. can you close it if we can?