✨ Support a list of maps in tilt-settings

[h0tbird]

What this PR does / why we need it:
As a developer I want to be able to define multiple Tilt providers per repository.
This is useful for developing CAPI providers that include multiple operators.

Anything else you would like to add:
My CAPI tilt-settings.json looks like this:

{
  "default_registry": "localhost:5000",
  "provider_repos": ["../cluster-api-provider-aws"],
  "enable_providers": ["aws", "eks-bootstrap"],
  "kustomize_substitutions": {
    "AWS_B64ENCODED_CREDENTIALS": "<REDACTED>",
    "EXP_MACHINE_POOL:=false": "false",
    "EXP_CLUSTER_RESOURCE_SET:=false": "false"
  }
}

And I tested two different CAPA tilt-settings.json:

{
  "name": "aws",
  "config": {
    "image": "gcr.io/k8s-staging-cluster-api-aws/cluster-api-aws-controller",
    "live_reload_deps": [
      "main.go", "go.mod", "go.sum", "api", "cmd", "controllers", "pkg"
    ]
  }
}

and this:

[
  {
    "name": "aws",
    "config": {
      "image": "gcr.io/k8s-staging-cluster-api-aws/cluster-api-aws-controller",
      "live_reload_deps": [
        "main.go", "go.mod", "go.sum", "api", "cmd", "controllers", "pkg"
      ]
    }
  },
  {
    "name": "eks-bootstrap",
    "config": {
      "context": "bootstrap/eks",
      "image": "gcr.io/k8s-staging-cluster-api-aws/eks-bootstrap-controller",
      "live_reload_deps": [
        "main.go", "api", "controllers"
      ]
    }
  }
]

Which issue(s) this PR fixes:
Fixes #3299

[k8s-ci-robot]

Hi @h0tbird. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[fabriziopandini]

/ok-to-test

[fabriziopandini]

/lgtm
please squash commits

[fabriziopandini]

/lgtm
over to @ncdc or @detiber for the final approval

[ncdc]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ncdc

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