SearxNG meta search api helper (#854)

This is a work in progress PR to track my progres.

## TODO:

- [x]  Get results using the specifed searx host
- [x]  Prioritize returning an  `answer`  or results otherwise
    - [ ] expose the field `infobox` when available
    - [ ] expose `score` of result to help agent's decision
- [ ] expose the `suggestions` field to agents so they could try new
queries if no results are found with the orignial query ?

- [ ] Dynamic tool description for agents ?
- Searx offers many engines and a search syntax that agents can take
advantage of. It would be nice to generate a dynamic Tool description so
that it can be used many times as a tool but for different purposes.

- [x]  Limit number of results
- [ ]   Implement paging
- [x]  Miror the usage of the Google Search tool
- [x] easy selection of search engines
- [x]  Documentation
    - [ ] update HowTo guide notebook on Search Tools
- [ ] Handle async 
- [ ]  Tests

###  Add examples / documentation on possible uses with
 - [ ]  getting factual answers with `!wiki` option and `infoboxes`
 - [ ]  getting `suggestions`
 - [ ]  getting `corrections`

---------

Co-authored-by: blob42 <spike@w530>
Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>

docs/modules/agents/tools.md

@@ -120,6 +120,14 @@ Below is a list of all supported tools and relevant information:
 - Extra Parameters: `google_api_key`, `google_cse_id`
 - For more information on this, see [this page](../../ecosystem/google_search.md)
 
+**searx-search**
+
+- Tool Name: Search
+- Tool Description: A wrapper around SearxNG meta search engine. Input should be a search query. 
+- Notes: SearxNG is easy to deploy self-hosted. It is a good privacy friendly alternative to Google Search. Uses the SearxNG API. 
+- Requires LLM: No
+- Extra Parameters: `searx_host`
+
 **google-serper**
 
 - Tool Name: Search