debt: remove async-timeout in favor of asyncio.timeout

[RohithPariki]

Fixes #2052

Description

This PR drops the deprecated async-timeout dependency in favor of the standard library's asyncio.timeout, as the functionality was upstreamed into Python 3.11+.

As discussed in the issue (and targeting the 2.0 milestone), this PR drops support for Python 3.10 to allow for the clean path of using the standard library directly without version-guarded imports.

Changes Made

• pyproject.toml: Removed async-timeout from dependencies and bumped requires-python (and related classifiers) to >=3.11.
• src/crawlee/_utils/time.py: Replaced async_timeout.timeout with asyncio.timeout inside the SharedTimeout class. Retained the existing context manager logic as asyncio.timeout also serves as a drop-in async context manager in Python 3.11+.

Verification

• Verified that SharedTimeout successfully catches operations exceeding the budget and properly propagates TimeoutError.
• Ran ruff to ensure formatting and linting rules are upheld.