archive(1.1) isolation: remove all other versions

[pepopowitz]

Note that this PR targets unsupported/1.1, and will never make it into main!

Description

Part of #2186

This is the Chonky Boi ™️ PR for isolating version 1.1, in which all other versions are removed from the unsupported/1.1 branch.

We will merge this PR in a red state, as it requires follow-up steps to fix the build.

Removes:

• version-1.2
• version-1.3
• version-8.0
• version-8.1
• version-8.2
• version 'next'
• optimize docs

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.