feat(fetcher): add configurable timeout for httpx fetcher (#782)

* feat(fetcher): add configurable timeout for httpx fetcher

* feat(documentation): add HTTP fetcher provider client and timeout configuration

* feat(fetcher): rename HTTPX_FETCHER_TIMEOUT to HTTP_FETCHER_TIMEOUT and update description

* fix(fetcher): format ClientSession initialization for better readability

* fix(fetcher): update ClientSession timeout initialization to use ClientTimeout

* fix(fetcher): improve readability of ClientSession initialization in HttpFetchProvider

* fix(fetcher): add missing comma in ClientSession initialization

* Fix docs lock file

---------

Co-authored-by: Dan Yishai <[email protected]>

Author: psardana

documentation/docs/getting-started/configuration.mdx

@@ -42,6 +42,8 @@ Please use this table as a reference.
 | AUTH_JWT_AUDIENCE                       |                                                                                                                                                                                 |         |
 | AUTH_JWT_ISSUER                         |                                                                                                                                                                                 |                           |
 | DD_TRACE_ENABLED                        | DataDog environment variable to globally enable/disable APM tracing. Set to `false` to disable tracing when using ddtrace v3.0.0+.                                          | false   |
+| HTTP_FETCHER_PROVIDER_CLIENT            | The client to use for fetching data, can be either aiohttp or httpx.                                                                                                            |         |
+| HTTP_FETCHER_TIMEOUT                    | The timeout for the data fetcher, in seconds.                                                                                                                         |         |
 
 ## OPAL Server Configuration Variables