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.kt

@@ -0,0 +1,16 @@
+// WITH_STDLIB
+
+// FILE: foo.kt
+package namespace1
+fun foo(): Int = 123
+
+// FILE: bar.kt
+package namespace2
+fun bar(): Int = 321
+
+// FILE: main.kt
+package namespace1.main
+
+import namespace1
+import namespace2
+fun foobar(): Int = foo() + bar()