[mod] switching from pyright to basedpyright (plus first rules)

pyrightconfig.json :

  for the paths searx, searxng_extra and tests, individual rules were
  defined (for example, in test fewer / different rules are needed than in the
  searx package

searx/engines/__builtins__.pyi :

  The builtin types that are added to the global namespace of a module by the
  intended monkey patching of the engine modules / replaces the previous
  filtering of the stdout using grep.

test.pyright_modified (utils/lib_sxng_test.sh) :

  static type check of local modified files not yet commited

make test :

  prerequisite 'test.pyright' has been replaced by 'test.pyright_modified'

searx/engines/__init__.py, searx/enginelib/__init__.py :

  First, minimal typifications that were considered necessary.

searx/enginelib/__init__.py

@@ -252,7 +252,7 @@ class Engine:  # pylint: disable=too-few-public-methods
     display_error_messages: bool
     """Display error messages on the web UI."""
 
-    proxies: dict
+    proxies: dict[str, dict[str, str]]
     """Set proxies for a specific engine (YAML):
 
     .. code:: yaml