Implement the shadow node for proper laying out Aztec on Android

[hypest]

Addresses #1091

This PR implements the shadow node logic for the Aztec wrapper custom React Native view. This is needed for better View calculations.

This work begun as an attempt to remove the need to specify the minHeight style on the Aztec wrapper. I think that the view should be able to update its height automatically within RN and the Android layout system, without us manually having to set it as a style prop. In that respect, the effort here is not finished; the minHeight style is still needed (try removing it and you'll see that the wrapper doesn't update its height properly, although its now initial height is much better than before). Although, my experiments so far with a basic demo app (in repo: https://github.com/hypest/RN060-aztec-experiments) seem to work and the Aztec wrapper there seems fine without specifying any minHeight.

Even in this state, the behavior in this PR is better than before and that's why I'm opening this PR.

Known issue: the height of the component seems smaller than the content text but only by a little. The onContentSizeChange logic repairs it but it's still visible. Besides, the glitch is minimized due to the work on #1076 and that's why this PR builds on top of that, albeit in a separate PR so #1076 doesn't get blocked/complex.

To test:

1. Run the demo app on Android
2. Put the caret in the middle or the end of the "Lorem ipsum" paragraph block
3. Split the block
4. Notice that the visual glitch of the existing block resizing is quite small

I have also
Update release notes:

• If there are user facing changes, I have added an item to RELEASE-NOTES.txt.

[marecar3]

Hey @hypest, I tested this branch a little bit and it seems that it's an improvement 👍

[daniloercoli]

❤️ Way better than before. LGTM!

[mkevins]

I'm getting this warning in AS about these lines for RTL compatibility:

For RtL compatibility, use setPaddingRelativeor ViewCompat.setPaddingRelative() when setting left/right padding. less... (Ctrl+F1) 
Inspection info:For RtL compatibility, use setPaddingRelativeor ViewCompat.setPaddingRelative() when setting left/right padding.

[mkevins]

This might be a local linting issue on my end.. I couldn't determine why it gave this warning when ReactTextUpdate merely inherits from java.lang.Object 🤔

[hypest]

I'm getting this warning in AS about these lines for RTL compatibility:

Good point. I've been actually mirroring the code in upstream's implementation of the TextInput shadow node here: https://github.com/facebook/react-native/blob/d88e4701fc46b028861ddcfa3e6ffb141b3ede3d/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactTextInputManager.java#L193-L197

I'm kinda torn but, I think it makes more sense at the moment to follow upstream's lead on this one. Alternatively, we can even completely remove the code to set the padding since it's not a real goal for this PR anyway. WDYT?

[mkevins]

I think it makes more sense at the moment to follow upstream's lead on this one.

I agree, this seems like the best way forward. I haven't tested many scenarios without the code (only the "Lorem ipsum" test in the description), and I'm unsure if there are scenarios where it would be important to have it. So keeping it close to upstream seems the sensible approach. LGTM!

[mkevins]

I tested these changes and it's very smooth now! 😃