KT-63748: Pack Swift Export Frontend into compiler plugin

Co-authored-by: Sergej Jaskiewicz <jaskiewiczs@icloud.com>


Merge-request: KT-MR-13351
Merged-by: Artem Olkov <artem.olkov@jetbrains.com>

plugins/swift-export/testData/simple.golden.kt

@@ -0,0 +1,19 @@
+import kotlin.native.internal.ExportForCppRuntime
+
+@ExportForCppRuntime("namespace1_main_foobar")
+public fun namespace1_main_foobar(): Int {
+    val result = namespace1.main.foobar()
+    return result
+}
+
+@ExportForCppRuntime("namespace1_foo")
+public fun namespace1_foo(): Int {
+    val result = namespace1.foo()
+    return result
+}
+
+@ExportForCppRuntime("namespace2_bar")
+public fun namespace2_bar(): Int {
+    val result = namespace2.bar()
+    return result
+}