Docs refactor (#480)

Big docs refactor! Motivation is to make it easier for people to find
resources they are looking for. To accomplish this, there are now three
main sections:

- Getting Started: steps for getting started, walking through most core
functionality
- Modules: these are different modules of functionality that langchain
provides. Each part here has a "getting started", "how to", "key
concepts" and "reference" section (except in a few select cases where it
didnt easily fit).
- Use Cases: this is to separate use cases (like summarization, question
answering, evaluation, etc) from the modules, and provide a different
entry point to the code base.

There is also a full reference section, as well as extra resources
(glossary, gallery, etc)

Co-authored-by: Shreya Rajpal <ShreyaR@users.noreply.github.com>

docs/ecosystem/pinecone.md

@@ -0,0 +1,20 @@
+# Pinecone
+
+This page covers how to use the Pinecone ecosystem within LangChain.
+It is broken into two parts: installation and setup, and then references to specific Pinecone wrappers.
+
+## Installation and Setup
+- Install the Python SDK with `pip install pinecone-client`
+## Wrappers
+
+### VectorStore
+
+There exists a wrapper around Pinecone indexes, allowing you to use it as a vectorstore,
+whether for semantic search or example selection.
+
+To import this vectorstore:
+```python
+from langchain.vectorstores import Pinecone
+```
+
+For a more detailed walkthrough of the Pinecone wrapper, see [this notebook](../modules/utils/combine_docs_examples/vectorstores.ipynb)