archive(1.2) isolation: automated steps

[pepopowitz]

Description

Part of #2188.

Note: this PR will be merged into the unsupported/1.2 branch. It will never make it into main.

Note: this PR will not go green. There are manual cleanup steps coming in a future PR that will make this branch green.

Continues the process of archival/isolation for version 1.2. Includes the following steps, which a computer did for me:

1. Exclude all other versions from version manifest file
2. Prevent the 1.0 site from being crawled
3. Fix the Dockerfile for local debugging
4. Update the swizzled theme components for the isolated version.
5. Update CI workflows.
6. Update the docusaurus.config.js.

See #2421 for a similar PR in a previous archived version, if that's helpful for comparison purposes during review.

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.