feat: New Core/ library (#1975)

Moves everything Camera related into `core/` / `Core/` so that it is better encapsulated from React Native.

Benefits:

1. Code is much better organized. Should be easier for collaborators now, and cleaner codebase for me.
2. Locking is fully atomically as you can now only configure the session through a lock/Mutex which is batch-overridable
    * On iOS, this makes Camera startup time **MUCH** faster, I measured speedups from **1.5 seconds** to only **240 milliseconds** since we only lock/commit once! 🚀 
    * On Android, this fixes a few out-of-sync/concurrency issues like "Capture Request contains unconfigured Input/Output Surface!" since it is now a single lock-operation! 💪 
3. It is easier to integrate VisionCamera outside of React Native (e.g. Native iOS Apps, NativeScript, Flutter, etc)

With this PR, VisionCamera V3 is up to **7x** faster than V2

package/ios/Extensions/AVCaptureOutput+mirror.swift

@@ -0,0 +1,52 @@
+//
+//  AVCaptureOutput+mirror.swift
+//  mrousavy
+//
+//  Created by Marc Rousavy on 18.01.21.
+//  Copyright © 2021 mrousavy. All rights reserved.
+//
+
+import AVFoundation
+
+extension AVCaptureOutput {
+  /**
+   Mirrors the video output if possible.
+   */
+  func mirror() {
+    connections.forEach { connection in
+      if connection.isVideoMirroringSupported {
+        connection.automaticallyAdjustsVideoMirroring = false
+        connection.isVideoMirrored = true
+      }
+    }
+  }
+
+  /**
+   Sets the target orientation of the video output.
+   This does not always physically rotate image buffers.
+
+   - For Preview, an orientation hint is used to rotate the layer/view itself.
+   - For Photos, an EXIF tag is used.
+   - For Videos, the buffers are physically rotated if available, since we use an AVCaptureVideoDataOutput instead of an AVCaptureMovieFileOutput.
+   */
+  func setOrientation(_ orientation: Orientation) {
+    // Camera Sensors are always in 90deg rotation.
+    // We are setting the target rotation here, so we need to rotate by 90deg once.
+    let cameraOrientation = orientation.rotateRight()
+
+    // Set orientation for each connection
+    connections.forEach { connection in
+      // TODO: Use this once Xcode 15 is rolled out
+      // if #available(iOS 17.0, *) {
+      //   let degrees = cameraOrientation.toDegrees()
+      //   if connection.isVideoRotationAngleSupported(degrees) {
+      //     connection.videoRotationAngle = degrees
+      //   }
+      // } else {
+      if connection.isVideoOrientationSupported {
+        connection.videoOrientation = cameraOrientation.toAVCaptureVideoOrientation()
+      }
+      // }
+    }
+  }
+}