[installer]: Add server chargebee configuration to the installer

[andrew-farries]

Description

One of the Webapp team's epics for Q2 is to use the Gitpod installer to deploy to Gitpod SaaS. In order to do that we will need to add additional configuration to the installer to make the output suitable for a SaaS deployment as opposed to a self-hosted deployment.

This PR makes it possible to configure the server component's chargebee configuration via new configuration surface in the experimental section of the installer config that allows specifying the name of a secret containing chargebee config. For installations on which payments should be enabled, we expect there to be a secret present in the cluster containing this configuration. For Gitpod SaaS, this is achieved via terraform as a cluster prerequisite:

https://github.com/gitpod-io/ops/blob/8fb50515adbfa90a3435f2148660f7de8d70c219/terraform/modules/gitpod/main.tf#L31-L38

Related Issue(s)

Part of #9097

How to test

Create an installer config file containing this experimental section:

experimental:
  webapp:
    server:
      chargebeeSecret: "chargebee-config"

Get a versions.yaml for use with the installer:

docker run -it --rm "eu.gcr.io/gitpod-core-dev/build/versions:${version}" cat versions.yaml > versions.yaml

Then invoke the installer as:

go run . render --debug-version-file versions.yaml --config /path/to/config --use-experimental-config

The server configmap will have enablePayment set to true and the server deployment will have an extra volume + volumemount:

        - mountPath: /chargebee
          name: chargebee-config
          readOnly: true

      - name: chargebee-config
        secret:
          secretName: chargebee-config

Release Notes

Allow chargebee payment config to be specified via the installer for SaaS installations.

Documentation

None.

[geropl]

Thx, tested and looks good! 👍

[corneliusludmann]

Do you think a single commit instead of 3 for such a rather small change would be also sufficient?

Otherwise, change looks good so far. 🚀

Holding in case you want to squash the commits.

/hold

[andrew-farries]

Holding in case you want to squash the commits.

Thanks, I've squashed down to one commit.

[andrew-farries]

/unhold