@W-21929529 SDK experience enhancement for function

[ritaagarwala-sf]

1. datacustomcode init --code-type function ( SearchIndexChunking is default use-in-feature )

Creates a function with below signature:

def function(request: SearchIndexChunkingV1Request, runtime: Runtime) -> SearchIndexChunkingV1Response:

And generates a test.json reading the signature of function. Sample test.json will look like below:

{
"input": [
{
"text": "sample_text",
"metadata": {}
}
],
"max_characters": 100,
"additional_params": {}
}

2. Customer can test function with below command:
   datacustomcode run ./payload/entrypoint.py --test-with payload/tests/test.json