d3: remove as many broken things as possible

[pepopowitz]

Part of #4799 , will merge into that PR's branch.

Description

Removes as much known-broken code and configuration as possible, to minimize the effort required to get the upgrade branch green.

All of these changes are temporary, and will eventually be resolved and reintroduced, as described in #4799's progress list.

Included

• temp: remove docLayoutComponent setting
• temp: remove old versions
• temp: remove broken theme components

When should this change go live?

• This is a bug fix, security concern, or something that needs urgent release support.
• This is already available but undocumented and should be released within a week.
• This on a specific schedule and the assignee will coordinate a release with the DevEx team. (apply hold label or convert to draft PR)
• This is part of a scheduled alpha or minor. (apply alpha or minor label)
• There is no urgency with this change and can be released at any time.

PR Checklist

• My changes are for an already released minor and are in /versioned_docs directory.
• My changes are for the next minor and are in /docs directory (aka /next/).

• My changes require an Engineering review, and I've assigned the Engineering DRI or delegate.
• My changes require a technical writer review, and I've assigned @camunda/tech-writers as a reviewer.

[pepopowitz]

build-docs is failing with errors on the improperly formatted markdown of the generated API docs. Next steps for the upgrade are to regenerate those docs and get versions next and current green.