[Flare] Bring Flare support to React Native Fabric

[trueadm]

This PR adds support for React Flare to React Native (Fabric only).

This includes much of the core work that was already done for ReactDOM's responder system. In fact much of it is copied – but I'm going to leave that intentionally copied for now. We can unify the shared logic in a follow up – but in order not to conflict with existing work on ReactDOM, it's separate for now.

I've also included a Flare version of the Press responder that works after doing some internal testing on iOS and Android with Fabric.

I'll also add tests for Press in a follow up, but first wanted to get the scaffolding implementation in without making this PR huge.

[sizebot]

Details of bundled changes.

Comparing: 9b0bd43...22ca010

react-native-renderer

File	Filesize Diff	Gzip Diff	Prev Size	Current Size	Prev Gzip	Current Gzip	ENV
ReactFabric-dev.js	+3.8%	+3.7%	688.17 KB	714.41 KB	146.33 KB	151.68 KB	RN_FB_DEV
ReactFabric-prod.js	🔺+0.6%	🔺+0.8%	260.97 KB	262.55 KB	44.99 KB	45.35 KB	RN_FB_PROD
ReactNativeRenderer-dev.js	0.0%	-0.0%	699.25 KB	699.25 KB	148.91 KB	148.91 KB	RN_OSS_DEV
ReactFabric-profiling.js	+0.6%	+0.7%	269.59 KB	271.18 KB	46.48 KB	46.83 KB	RN_FB_PROFILING
ReactNativeRenderer-prod.js	0.0%	-0.0%	268.64 KB	268.64 KB	46.21 KB	46.21 KB	RN_OSS_PROD
ReactNativeRenderer-dev.js	0.0%	-0.0%	699.35 KB	699.35 KB	148.96 KB	148.96 KB	RN_FB_DEV
ReactNativeRenderer-prod.js	0.0%	-0.0%	268.63 KB	268.63 KB	46.22 KB	46.22 KB	RN_FB_PROD
ReactFabric-dev.js	+3.8%	+3.7%	688.07 KB	714.31 KB	146.29 KB	151.63 KB	RN_OSS_DEV
ReactFabric-prod.js	🔺+0.6%	🔺+0.8%	260.97 KB	262.55 KB	44.98 KB	45.33 KB	RN_OSS_PROD
ReactFabric-profiling.js	+0.6%	+0.7%	269.59 KB	271.18 KB	46.47 KB	46.82 KB	RN_OSS_PROFILING

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