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>

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

- 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

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  prerequisite 'test.pyright' has been replaced by 'test.pyright_modified'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

The definition of a context name belongs in the abstract base class (was
previously only in the concrete implementation for the SQLite adapter).

Suggested-by: @dalf https://github.com/searxng/searxng/pull/4650#discussion_r2069873853
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

The entries in the catalog of search languages are build up from the "Engine
Traits" [1] and which entries are included in the catalog is controlled qby two
threshold values [2].

If possible, the values should ensure that no languages or regions disappear
from the catalog of search languages [3].

The threshold values should have been adjusted in commit 30a8204:

- ``min_eng_per_region = 18``
- ``min_eng_per_lang = 22``

Because the threshold values were not adjusted, many entries were missing in the
search language catalog.  This bug has been fixed with this patch: the threshold
values have been adjusted and the catalog of search languages has been completed
again.

[1] https://docs.searxng.org/dev/engines/enginelib.html#module-searx.enginelib.traits
[2] https://github.com/searxng/searxng/blob/96a6e3dcb2283fa7ad9db4172a00582073a166d7/searxng_extra/update/update_engine_traits.py#L104-L105
[3] https://github.com/searxng/searxng/blob/master/searx/sxng_locales.py

Closes: https://github.com/searxng/searxng/issues/4519
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

The class ReslutContainer has been revised, it can now handle the typed Result
items of classes:

- MainResult
- LegacyResult (a dict wrapper for backward compatibility)

Due to the now complete typing of theses three clases, instead of the *getitem*
accesses, the fields can now be accessed directly via attributes (which is also
supported by the IDE).

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

In the past, some files were tested with the standard profile, others with a
profile in which most of the messages were switched off ... some files were not
checked at all.

- ``PYLINT_SEARXNG_DISABLE_OPTION`` has been abolished
- the distinction ``# lint: pylint`` is no longer necessary
- the pylint tasks have been reduced from three to two

  1. ./searx/engines -> lint engines with additional builtins
  2. ./searx ./searxng_extra ./tests -> lint all other python files

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