[stable/drupal] Make liveness and readiness probes configurable

[scottrigby]

Reasoning for this PR is explained in the values file comments:

Drupal core exposes /user/login to unauthenticated requests, making it a good
default liveness and readiness path. However, that may not always be the
case. For example, if the image value is overridden to an image containing a
module that alters that route, or an image that does not auto-install Drupal.

[k8s-ci-robot]

Hi @scottrigby. Thanks for your PR.

I'm waiting for a kubernetes 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.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[scottrigby]

Same version bump as #1232. Will update version as needed after one or the other is merged first.

[prydonius]

/ok-to-test

[viglesiasce]

Closing in favor of #1449