[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/engines/metacpan.py

@@ -3,7 +3,6 @@
 """
 
 from urllib.parse import urlunparse
-from json import dumps
 
 # about
 about = {
@@ -56,7 +55,7 @@ def request(query, params):
     query_data = query_data_template
     query_data["query"]["multi_match"]["query"] = query
     query_data["from"] = (params["pageno"] - 1) * number_of_results
-    params["data"] = dumps(query_data)
+    params["json"] = query_data
     return params