Upgrade to Python 3.13

[achimnol]

• astral-sh/python-build-standalone v20241219 already provides Python 3.13.1 builds.
  • For now, we are not targeting the free-threaded (nogil) builds as our code base relies on asyncio to multiplex multiple socket connections and offloads file I/O operations using threads. Also aiotools.server provides a multiprocess architecture to scale out the apps.
• Upgrade pants.toml and other places referring prior Python major upgrade PRs:
  • Support Python 3.12 #1768
  • setup: Upgrade to Python 3.11 #1012
  • Upgrade to Python 3.10 #300
• Upgrade aiohttp to 3.11 release (and yarl to 1.18) #3233
• Upgrade uvloop to v21.0
• Upgrade janus to v2.0 to support the new queue shutdown mechanisms and asyncio.QueueShutdown
  • aiotools, aiofiles should be also updated/checked with the compatibility.
• mypyc-optimized mypy wheels for linux-aarch64 in lablup/backend.ai-oven
• Replace some use cases of short-lived asyncio.gather(*, return_exceptions=True) with the rewritten asyncio.as_completed() API