Flutter: Deliver repo README and reference docs for SDK GA

[jhaaaa]

Eng:

• Update repo README to reflect features in the GA version of the Flutter SDK
• Update code annotations to generate reference docs that reflect features in the GA version of the Flutter SDK

Docs (@jhaaaa)

• Provide copy and style edits to repo README. In addition to publishing the README to the repo, J-Ha will also publish the README content as a quickstart tutorial on xmtp.org.
• Coordinate with Eng to generate reference docs in a format that J-Ha can publish to xmtp.org

[jhaaaa]

Generated HTML reference docs for xmtp-flutter.

Hoping to be able to generate Markdown to easily insert the content into Docusaurus. Can't seem to find the command to do it. @dmccartney offered to help on Monday. TY!

[jhaaaa]

• Reference docs: Team made the call to link to reference docs here https://pub.dev/documentation/xmtp/latest/xmtp/xmtp-library.html -- instead of reshaping generated docs to fit on xmtp.org.

• README/Quickstart tutorial: Opened PR to update README in repo to reflect GA. Dan reviewing: https://github.com/xmtp/xmtp-flutter/pull/45

• Opened draft PR to publish README/Quickstart and link to reference docs on xmtp.org: https://github.com/xmtp/xmtp-dot-org/pull/262

• Open item: Setting up Algolia to index the reference docs on the external site. I don't think it is a blocker for publication, but I have customer support and discussion forum issues open asking for guidance about a theory I have about how it could work. If I don't get guidance, I'll just try it in the repo - but wanted to get some hint of validation first.

[jhaaaa]

Heard back from Algolia about indexing external sites. They call it "multi-index search" and it requires using an InstantSearch.js file: https://www.algolia.com/doc/guides/building-search-ui/ui-and-ux-patterns/multi-index-search/js/

Currently, xmtp-dot-org uses an algolia.config.json file for Algolia configuration - not InstantSearch.js. Switching might take some work - I'm asking Algolia for some guidance on this - but it takes them days between messages to reply - so this might take a while.

This feature might also become very simple once we get access to their crawler UI - which Matt and I have also been pinging them about.

For launch, we may just need to link - and set up multi-index search once we have the info and resources to do so.

In the meantime, I can just list the classes, properties, and enums to make at least those high-level keywords searchable on xmtp.org.

[jhaaaa]

Delivered in https://github.com/xmtp/xmtp-dot-org/pull/311