Separate Images for Light and Dark Mode

[robscott]

What would you like to be added: As a prerequisite for #2896 to be merged, we'll need to introduce separate images for light and dark mode. This can be done by either converting diagrams to mermaid.js, or creating equivalent dark mode images and following the documentation to specify the mode they're intended to be used with.

Why this is needed: It would be very helpful to have light and dark mode for our docs, but unfortunately our current documentation relies on images that don't work well in dark mode. This work would unblock dark mode capabilities for our documentation.

[robscott]

/help

[k8s-ci-robot]

@robscott: This request has been marked as needing help from a contributor.

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In response to [this](https://github.com/kubernetes-sigs/gateway-api/issues/3146): >/help Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository.

[jongwooo]

/assign

[jongwooo]

Hi @robscott , I've checked the images, and it's a lot to process by myself, so it's going to take a while. How about turning this into an umbrella issue and working with contributors to change it?