Summary:
This diff moves the iOS descriptors and other layout helpers into its own buck target. Earlier everything was part of the FlipperKitLayoutPlugin target. When kcui, tried to add macos descriptors, we realised that FlipperKitLayoutPlugin doesn't have macos platform in it and thus he had to put #if TARGET_OS_SIMULATOR check in iOS descriptors and at some other places.
In order to make the integration easier I decided to split the Layout Plugin in following way.
```
FlipperKitLayoutPlugin
-> FlipperKitLayoutIOSDescriptors (platform set as IOS)
-> FlipperKitLayoutHelpers (used in iOS Descriptors and usefule for Macos too)
-> FlipperKitLayoutMacOSDescriptors(coming soon by kcui)(platform set as MacOS)
```
Reviewed By: kcui
Differential Revision: D27127587
fbshipit-source-id: f108ef81914297e93c886fe53dabf0a4bf11ebc1
Summary: Similar to D21040424 and D21040426.
Reviewed By: Andrey-Mishanin
Differential Revision: D21335955
fbshipit-source-id: 5e8326915e54647c77fb241ad2ed4eaa55d0cfe2
Summary:
Before this diff, Flipper showed *leaf* views created by ComponentKit, but not any intermediate views. Now we show both.
A new node type `SKComponentMountedView` is used for this purpose. Its descriptor `SKComponentMountedViewDescriptor` mostly delegates to its view's descriptor, but redirects back into ComponentKit for children.
Reviewed By: Andrey-Mishanin
Differential Revision: D21130997
fbshipit-source-id: b3c12ea7cc1200962b3ba7c269c48d68b1809948
