Add alternative constructor for AsyncioIndex (#451)

## Problem

If you only care about doing async index oeprations, it's cumbersome to
have to manage nested async contexts by going through the
`PineconeAsyncio` class.

## Solution

This is a very simple change that enables people to create an async
index client.

## Usage

You can now do index operations via asyncio like this:

```python
import asyncio
from pinecone import Pinecone

async def main():
    async with Pinecone().IndexAsyncio(host='myhost') as idx:
        await idx.uspert(...) # do async things

asyncio.run(main())
```

## Type of Change

- [x] New feature (non-breaking change which adds functionality)

Author: jhamon

pinecone/control/pinecone.py

@@ -25,7 +25,7 @@
 from .langchain_import_warnings import _build_langchain_attribute_error_message
 from pinecone.utils import docslinks
 
-from pinecone.data import _Index, _Inference
+from pinecone.data import _Index, _Inference, _AsyncioIndex
 from pinecone.enums import (
     Metric,
     VectorType,
@@ -314,6 +314,24 @@ def Index(self, name: str = "", host: str = "", **kwargs):
             **kwargs,
         )
 
+    def IndexAsyncio(self, host: str, **kwargs):
+        api_key = self.config.api_key
+        openapi_config = self.openapi_config
+
+        if host is None or host == "":
+            raise ValueError("A host must be specified")
+
+        check_realistic_host(host)
+        index_host = normalize_host(host)
+
+        return _AsyncioIndex(
+            host=index_host,
+            api_key=api_key,
+            openapi_config=openapi_config,
+            source_tag=self.config.source_tag,
+            **kwargs,
+        )
+
 
 def check_realistic_host(host: str) -> None:
     """@private

tests/integration/data_asyncio/test_client_instantiation.py

@@ -0,0 +1,18 @@
+import pytest
+from pinecone import Pinecone
+from ..helpers import random_string, embedding_values
+
+
+@pytest.mark.asyncio
+async def test_instantiation_through_non_async_client(index_host, dimension):
+    asyncio_idx = Pinecone().IndexAsyncio(host=index_host)
+
+    def emb():
+        return embedding_values(dimension)
+
+    # Upsert with tuples
+    await asyncio_idx.upsert(
+        vectors=[("1", emb()), ("2", emb()), ("3", emb())], namespace=random_string(10)
+    )
+
+    await asyncio_idx.close()