Add WAMR API bindings in Python (#1959)

Before adding the new bindings:
1. Moved wasm-c-api in a subfolder wasmcapi in the package.
2. Adapted the tests to be able to run in this new structure.

New:
1. Added the WAMR API in another folder wamrapi in the same level as wasm-c-api.
2. Created an OOP proposal.
3. Added an example using this proposal.

language-bindings/python/wasm-c-api/samples/hello_oop.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2019 Intel Corporation.  All rights reserved.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+import ctypes
+from wamr import *
+
+
+def hello_callback():
+    print("Calling back...")
+    print("> Hello World!")
+
+
+def main():
+    print("Initializing...")
+    engine = Engine()
+    store = Store(engine)
+
+    print("Loading binary...")
+    print("Compiling module...")
+    module = Module.from_file(engine, "./hello.wasm")
+
+    print("Creating callback...")
+    hello = Func(store, FuncType([], []), hello_callback)
+
+    print("Instantiating module...")
+    instance = Instance(store, module, [hello])
+
+    print("Extracting export...")
+    run = instance.exports(store)["run"]
+
+    print("Calling export...")
+    run(store)
+
+    print("Shutting down...")
+    print("Done.")
+
+
+if __name__ == "__main__":
+    main()