archive(1.0) isolation: manual steps

[pepopowitz]

Description

Part of #2185.

Manual tasks to isolate a site for version 1.0, including:

• Update the docusaurus.config.js
• Update broken links
• Update htaccess rules

See #2235 for a comparable PR of a previous version (0.26). The CI workflow updates in that PR were covered by #2318 in this version.

This is the final PR for isolating version 1.0. After this is merged, I'll deploy the 1.0 version to unsupported.docs.camunda.io/1.0.

When should this change go live?

• This change is not yet live and should not be merged until {ADD_DATE} (apply hold label or convert to draft PR)?
• There is no urgency with this change.
• This change or page is part of a marketing blog, conference talk, or something else on a schedule.
• This functionality is already available but undocumented.
• This is a bug fix or security concern.

PR Checklist

• I have added changes to the relevant /versioned_docs directory, or they are not for an already released version.
• I have added changes to the main /docs directory (aka /next/), or they are not for future versions.
• My changes require an Engineering review, and I've assigned an engineering manager or tech lead as a reviewer, or my changes do not require an Engineering review.
• My changes require a technical writer review, and I've assigned @christinaausley as a reviewer, or my changes do not require a technical writer review.