feat: Add cmake & ninja build requirements only when needed

[mgorny]

Rather than listing cmake and ninja build requirements unconditionally, add them to setup_requires when they are necessary -- that is, when using skbuild and when the system installations of these tools are not available. This avoids installing the packages unnecessarily, and improves portability by using downstream patched CMake version when available.

[mgorny]

Gentle ping.

[ddelange]

@maartenbreddels can you please merge #2449 so CI goes green and this PR can pull latest master?

[ddelange]

@mgorny master now contains the latest fixes for CI and numpy v2 support

[mgorny]

Ah, sorry, I didn't realize I was expected to merge/rebase it against master.

[ddelange]

@maartenbreddelsai flakey test failure, only on windows+3.12?

____________________ test_string_buffers[df_factory_numpy] ____________________

df_factory = <function df_factory_numpy.<locals>.create at 0x0000017F6A4F7A60>

    def test_string_buffers(df_factory):
        data = ["foo", "bar"]
        x = np.array(data, dtype="U8")
        df = df_factory(x=x)
        if isinstance(df["x"].values, pa.lib.ChunkedArray):
            pytest.xfail()
        interchange_df = df.__dataframe__()
        roundtrip_df = _from_dataframe_to_vaex(interchange_df)
>       assert roundtrip_df["x"].tolist() == data
               ^^^^^^^^^^^^^^^^^^^^^^^^^^

tests\dataframe_protocol_test.py:435: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
C:\hostedtoolcache\windows\Python\3.12.10\x64\Lib\site-packages\vaex\expression.py:806: in tolist
    return values.to_pylist()
           ^^^^^^^^^^^^^^^^^^
pyarrow\\array.pxi:1775: in pyarrow.lib.Array.to_pylist
    ???
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

>   ???
E   UnicodeDecodeError: 'utf-8' codec can't decode byte 0x80 in position 0: invalid start byte