Add reference docs for past releases

[tjtelan]

Goal is to automate the collection of docs directly from the repos and provide them in a list by their stable version number.

There are lots of different artifacts so this will probably be a tracking issue until there's a maintainable way to collect these.

CLI docs

• Fluvio CLI
• SMDK CLI
• fluvio-channel CLI
• fluvio-run CLI
• fluvio-cloud CLI

API docs

• Rust API
• Python API
• Node API
• Java API

Connector docs

Inbound

• http
• kafka
• mqtt

Outbound

• kafka
• sql

Certified Hub SmartModules

• jolt
• json-sql
• regex

(A stretch goal is to include Changelogs in addition to docs, but that's large enough to deserve its own issue.)

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There are 2 parts to this strategy

1. We need to update release a lot of the pipelines to add the generated docs to Github Releases.
2. Write the automation to collect the latest docs

Just a suggestion for implementation, but I would like to maintain a list of the docs types in https://github.com/infinyon/fluvio-website/tree/master/data. This list will allow us to build a template for hugo use for generating links.