Explicitly declare stability levels of declarations in kotlinx.cinterop package

* @ExperimentalForeignApi for all declarations that operate on
    unmanaged memory (i.e. pointers and references)
* @BetaInteropApi for the rest of the interoperability declarations,
    namely Swift/CInterop-specific interfaces and convenience-functions

### Implementation details

* Some typealiases are not marked explicitly because it crashes the compiler,
    yet their experimentality is properly propagated
* License header is adjusted where it previously had been existing
* Deprecated with ERROR interop declarations that are deprecated for more than
    two years are removed
* WASM target interop declarations are deprecated
* Deliberately make Boolean.toByte and Byte.toBoolean foreign-experimental to scare
    people away

^KT-57728 fixed

Merge-request: KT-MR-9788
Merged-by: Vsevolod Tolstopyatov <qwwdfsad@gmail.com>

kotlin-native/backend.native/build.gradle

@@ -1,11 +1,14 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
 import org.jetbrains.kotlin.cpp.CppConsumerPlugin
 import org.jetbrains.kotlin.cpp.CppUsage
 import org.jetbrains.kotlin.cpp.DependencyHandlerExKt
 import org.jetbrains.kotlin.tools.NativePluginKt
-/*
- * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
- * that can be found in the LICENSE file.
- */
+
+
 buildscript {
     apply from: "../../kotlin-native/gradle/kotlinGradlePlugin.gradle"
     apply plugin: 'project-report'
@@ -31,7 +34,12 @@ sourceSets {
 
 compileCompilerKotlin {
     kotlinOptions.jvmTarget = "1.8"
-    kotlinOptions.freeCompilerArgs += ['-opt-in=kotlin.RequiresOptIn', '-opt-in=org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI', '-Xskip-prerelease-check']
+    kotlinOptions.freeCompilerArgs += [
+            '-opt-in=kotlin.RequiresOptIn',
+            '-opt-in=org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI',
+            "-opt-in=kotlinx.cinterop.BetaInteropApi",
+            "-opt-in=kotlinx.cinterop.ExperimentalForeignApi",
+            '-Xskip-prerelease-check']
 }
 
 compileCli_bcKotlin {