[mod] addition of various type hints / tbc

- pyright configuration [1]_
- stub files: types-lxml [2]_
- addition of various type hints
- enable use of new type system features on older Python versions [3]_
- ``.tool-versions`` - set python to lowest version we support (3.10.18) [4]_:
  Older versions typically lack some typing features found in newer Python
  versions.  Therefore, for local type checking (before commit), it is necessary
  to use the older Python interpreter.

.. [1] https://docs.basedpyright.com/v1.20.0/configuration/config-files/
.. [2] https://pypi.org/project/types-lxml/
.. [3] https://typing-extensions.readthedocs.io/en/latest/#
.. [4] https://mise.jdx.dev/configuration.html#tool-versions

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

searx/botdetection/_helpers.py

@@ -53,7 +53,7 @@ def too_many_requests(network: IPv4Network | IPv6Network, log_msg: str) -> werkz
     return flask.make_response(('Too Many Requests', 429))
 
 
-def get_network(real_ip: IPv4Address | IPv6Address, cfg: config.Config) -> IPv4Network | IPv6Network:
+def get_network(real_ip: IPv4Address | IPv6Address, cfg: "config.Config") -> IPv4Network | IPv6Network:
     """Returns the (client) network of whether the ``real_ip`` is part of.
 
     The ``ipv4_prefix`` and ``ipv6_prefix`` define the number of leading bits in
@@ -71,7 +71,7 @@ def get_network(real_ip: IPv4Address | IPv6Address, cfg: config.Config) -> IPv4N
 
     prefix: int = cfg["botdetection.ipv4_prefix"]
     if real_ip.version == 6:
-        prefix: int = cfg["botdetection.ipv6_prefix"]
+        prefix = cfg["botdetection.ipv6_prefix"]
     network = ip_network(f"{real_ip}/{prefix}", strict=False)
     # logger.debug("get_network(): %s", network.compressed)
     return network