[core eng] modern CICD

[maxmwang]

Primarily building off @Chengming-Li great work on testCICD.

This PR introduces CICD workflows via Github Actions for:

• production in cd-prod.yaml. Manually triggered, must be reviewed.
• staging in cd-stage.yaml. Automatically triggered on push to master (and gql for now).
• development in cd-dev.yaml. Manually triggered, does not need review.

Manually triggered workflows use the workflow dispatch trigger. To trigger these, go into the "Actions" tab, select the correct action on the left panel, then click "Run workflow".

The development workflow also initiates a pod that cleans up the dev install after a certain amount of seconds, inputted from engineers when first running the dev workflow. There is no enforced cap, but please keep this number small.

[mathhulk]

I'd strongly recommend using reusable workflows when you have multiple workflows which do practically the same thing:

cd.yaml

name: Deploy

on:
  workflow_call:
    inputs:
      environment:
        type: string
        required: true
      ...

# All examples
env:
  GKE_CLUSTER: main-cluster
  GKE_ZONE: us-central1-c
  VAR_TAG: ${{ format('tag-{0}', inputs.environment) }}
  ...

jobs:
  deploy:
    name: Build and Deploy
    runs-on: ubuntu-latest-m

    steps:
      ...

cd-prod.yaml

name: Deploy to Production

on:
  workflow_dispatch:
  push:
    branches: ["main"]
    paths: ["apps/*"]

jobs:
  deploy:
    uses: ./.github/workflows/cd.yaml
    secrets: inherit
    with:
      environment: prod
      ...