docs: add langchain-scraperapi (#31973)

Adds documentation for the integration langchain-scraperapi, which
contains 3 tools using the ScraperAPI service.

The tools give AI agents the ability to

Scrape the web and return HTML/text/markdown
Perform Google search and return json output
Perform Amazon search and return json output

For reference, here is the official repo for langchain_scraperapi:
https://github.com/scraperapi/langchain-scraperapi

libs/packages.yml

@@ -749,3 +749,6 @@ packages:
 - name: langchain-zeusdb
   repo: zeusdb/langchain-zeusdb
   path: libs/zeusdb
+- name: langchain-scraperapi
+  path: .
+  repo: scraperapi/langchain-scraperapi