…ok#3038)

* Start new template guide

This is a first iteration. I want to get feedback on a few aspects, so
starting from here as a baseline.

* Update title

* Use tabs for target OS

Set up matching the style of "Getting Started", except I kept the
headers inside the tabs for now as it makes for a useful right-hand TOC.

* Capitalize New Architecture, simplify

* Preliminary section for Hermes

Add section for recommending enabling Hermes. Not sure of contents yet,
and still have to test.

* Reword to emphasize importance of Hermes usage

* Show new arch in use

* Add build speed article link

* Add pro tip for pod install alias

* Restructure, repeat less

Favor linking to original setup guide instead of repeating content.

* Note about Expo

* Include command on uninstalling global CLI

* How to learn more

* Remove headers in tabs

They don't work correctly with the righthand TOC.

* Make header more clear

* Use quote block less often

There was way too much yellow.

* Opt for instructions using XCode

Because `xcodebuild clean` already failed me once when XCode GUI clean
worked.

* Fix lint issue

* Improve wording

* Use product name

* Fix line wraps

* Reword based on feedback

* Note use of bundle install

* Pod removal instructions

Also standardize on using yarn scripts from template for commands, it's
a little confusing to see the mix of `npx` and `yarn` once we start
referring to `yarn pod-install`

* Convert quotes to admonitions

* Convert Note: to admonitions

* Feedback: Change admonitions to caution

* PR feedback

* First draft of landing page

* Add migration and backwards compatibility links

* lint fix

* Restructure slightly, leaning more on context from Why a New Architecture

* Don't need md in links

* Suggested rewording

* Rephrase pillar summaries

…ok#3039)

…facebook#3040)

* [Feat] Add intro for Fabric Components

* feat: add guide to create a Fabric Component

* [Feat] Add intro for Fabric Components

* feat: add guide to create a Fabric Component

* Beginning of guide/folder structure

* WIP JS Spec

* specification section

* Configuration

* native code intro

* Must be named Spec

* Best stab at iOS native code, but I don't know how to describe what's going on in the code very well. Extrapolated what I could.

* Android instructions

iOS isn't working for me. Builds, but can't load module.

Writing up Android auto-linking next because the steps I tested did
work.

* Include linking instructions from RNNArch repo

* Add example JavaScript

* native modules link

* Address quick feedback items

* Remove, fix for rebased branch

* fix TM parameter on Android

* Revert to 'Codegen' casing

* Revert folly version change

2021.07.22 is for current version on main

* fix typo

* getTurboModule explainer

* Sentence edits

- Fix acronym bolding
- Change wording to "recommended" because "standard" has other
  connotations of possibly being required
- Parentheses unnecessary, distracting

* Remove TODO for now

Getting inconsistent results here, not sure if this is wrong or not;
removing TODO for now so it doesn't block anything

* ABI rephrase, more in line with new Fabric guide wording

* Explain shared C++ code more

* feat: add guide to create a Fabric Component

* feat: add guide to create a Fabric Component

* package.json description

* Lint fixes

* fix: Move JS constants to reduce changes

* fix: Remove newline

* feat: add required step for Android Codegen

* fix: use the proper links

Co-authored-by: Riccardo Cipolleschi <cipolleschi@fb.com>

correcting the article

Co-authored-by: Riccardo <riccardo.cipolleschi@gmail.com>