rename repo namespace to langchain-ai (#11259)

### Description
renamed several repository links from `hwchase17` to `langchain-ai`.

### Why
I discovered that the README file in the devcontainer contains an old
repository name, so I took the opportunity to rename the old repository
name in all files within the repository, excluding those that do not
require changes.

### Dependencies
none

### Tag maintainer
@baskaryan

### Twitter handle
[kzk_maeda](https://twitter.com/kzk_maeda)

CITATION.cff

@@ -5,4 +5,4 @@ authors:
   given-names: "Harrison"
 title: "LangChain"
 date-released: 2022-10-17
-url: "https://github.com/hwchase17/langchain"
+url: "https://github.com/langchain-ai/langchain"