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/wamr-api/README.md

@@ -0,0 +1,25 @@
+# WARM API
+
+## Examples
+
+Copy in `language-bindings/python/wamr/libs` the library `libiwasm` generated from `product-mini/platforms`.
+
+There is a [simple example](./samples/main.py) to show how to use bindings.
+
+```
+python samples/main.py
+```
+
+## Update WAMR API bindings
+
+Install requirements,
+
+```
+pip install -r requirements.txt
+```
+
+Run the following command,
+
+```sh
+ctypesgen ../../../../core/iwasm/include/wasm_export.h -l ../libs/libiwasm.so -o iwasm.py
+```

language-bindings/python/wamr-api/requirements.txt

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+ctypesgen==1.1.1

language-bindings/python/wamr-api/samples/compile.sh

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+#!/bin/sh
+
+# Copyright (C) 2019 Intel Corporation.  All rights reserved.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+/opt/wasi-sdk/bin/clang     \
+    -O0 -z stack-size=4096 -Wl,--initial-memory=65536 \
+    -Wl,--strip-all,--no-entry -nostdlib \
+    -Wl,--export=sum\
+    -Wl,--allow-undefined \
+    -o test.wasm sum.c

language-bindings/python/wamr-api/samples/main.py

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+# Copyright (C) 2019 Intel Corporation.  All rights reserved.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+from wamr.wamrapi.wamr import Engine, Module, Instance, ExecEnv
+from ctypes import c_uint
+import pathlib
+
+def main():
+    engine = Engine()
+    module = Module.from_file(engine, pathlib.Path(__file__).parent / "sum.wasm")
+    module_inst = Instance(module)
+    exec_env = ExecEnv(module_inst)
+
+    func = module_inst.lookup_function("sum")
+
+    argv = (c_uint * 2)(*[10, 11])
+    exec_env.call(func, len(argv), argv)
+    print(argv[0])
+
+
+if __name__ == "__main__":
+    main()

language-bindings/python/wamr-api/samples/sum.c

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+/*
+ * Copyright (C) 2019 Intel Corporation.  All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+#include <stdio.h>
+
+int
+sum(int a, int b)
+{
+    return a + b;
+}