add support for socks proxies

[matecsaj]

Socks4 and Socks5 are stealthier than HTTP and HTTPS, so please add support for using Socks proxies.

However, be cautious—there was a time when Playwright rejected non-anonymous Socks proxies. I'm not sure about the current status.

Test code:

import asyncio
from crawlee.proxy_configuration import ProxyConfiguration

async def config_proxy() -> ProxyConfiguration:
    # Create and return a ProxyConfiguration object.
    proxy_configuration = ProxyConfiguration(
        tiered_proxy_urls=[
            # No proxy tier. (Not needed, but optional in case you do not want to use any proxy on lowest tier.)
            # [None],
            # lower tier, cheaper, preferred as long as they work
            ['https://example.com:8080', 'https://example.com:8080'],
            # higher tier, more expensive, used as a fallback
            ['socks4://example.com:8080', 'socks5://example.com:8080'],
        ]
    )

    return proxy_configuration

asyncio.run(config_proxy())

Terminal output:

/Users/matecsaj/PycharmProjects/wat-crawlee/venv/bin/python /Users/matecsaj/Library/Application Support/JetBrains/PyCharm2024.3/scratches/scratch_1.py 
Traceback (most recent call last):
  File "/Users/matecsaj/Library/Application Support/JetBrains/PyCharm2024.3/scratches/scratch_1.py", line 19, in <module>
    asyncio.run(config_proxy())
    ~~~~~~~~~~~^^^^^^^^^^^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ~~~~~~~~~~^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
  File "/Library/Frameworks/Python.framework/Versions/3.13/lib/python3.13/asyncio/base_events.py", line 720, in run_until_complete
    return future.result()
           ~~~~~~~~~~~~~^^
  File "/Users/matecsaj/Library/Application Support/JetBrains/PyCharm2024.3/scratches/scratch_1.py", line 6, in config_proxy
    proxy_configuration = ProxyConfiguration(
        tiered_proxy_urls=[
    ...<6 lines>...
        ]
    )
  File "/Users/matecsaj/PycharmProjects/wat-crawlee/venv/lib/python3.13/site-packages/crawlee/proxy_configuration.py", line 103, in __init__
    [[URL(url) for url in tier if self._url_validator.validate_python(url)] for tier in tiered_proxy_urls]
                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^
  File "/Users/matecsaj/PycharmProjects/wat-crawlee/venv/lib/python3.13/site-packages/pydantic/type_adapter.py", line 412, in validate_python
    return self.validator.validate_python(
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        object,
        ^^^^^^^
    ...<3 lines>...
        allow_partial=experimental_allow_partial,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
pydantic_core._pydantic_core.ValidationError: 1 validation error for function-wrap[wrap_val()]
  URL scheme should be 'http' or 'https' [type=url_scheme, input_value='socks4://example.com:8080', input_type=str]
    For further information visit https://errors.pydantic.dev/2.10/v/url_scheme

Process finished with exit code 1