[mod] addition of various type hints / engine processors

Continuation of #5147 .. typification of the engine processors.

BTW:

- removed obsolete engine property https_support
- fixed & improved currency_convert
- engine instances can now implement a engine.setup method

[#5147] https://github.com/searxng/searxng/pull/5147

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/network/client.py

@@ -138,7 +138,7 @@ def get_transport_for_socks_proxy(
         password=proxy_password,
         rdns=rdns,
         loop=get_loop(),
-        verify=_verify,
+        verify=_verify,  # pyright: ignore[reportArgumentType]
         http2=http2,
         local_address=local_address,
         limits=limit,