Do not store .cpp/.h files inside src/main/java - jscexecutor

[cortinico]

Summary:
Current we expose native code (.h, .cpp) inside the src/main/java folder.
This is making impossible for users on New Architecture to open the project
inside Android Studio.

The problem is that the src/main/java is reserved to Java/Kotlin sources only.
AGP 7.2 also removed support for mixed source roots:

https://developer.android.com/studio/releases/gradle-plugin#duplicate-content-roots
This is essentially forcing users to write Java code without any autocompletion
as all the React Native Java classes are considered C++ files.

I'm addressing this issue folder by folder by moving them
from ReactAndroid/src/main/java/com/facebook/... to ReactAndroid/src/main/jni/react/...

This is the diff for jscexecutor

Changelog:
[Internal] [Changed] - Do not store .cpp/.h files inside src/main/java - jscexecutor

Reviewed By: sshic

Differential Revision: D38615007

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D38615007

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: 296d7db
Branch: main

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	7,614,927	-48
android	hermes	armeabi-v7a	7,029,884	-39
android	hermes	x86	7,914,966	-33
android	hermes	x86_64	7,888,565	-59
android	jsc	arm64-v8a	9,490,950	-34
android	jsc	armeabi-v7a	8,268,794	-32
android	jsc	x86	9,428,601	-30
android	jsc	x86_64	10,021,326	-59

Base commit: 296d7db
Branch: main

[react-native-bot]

This pull request was successfully merged by @cortinico in be39184.

^{When will my fix make it into a release? | Upcoming Releases}