Enable discord.py logger by default.

[Jerrie-Aries]

Refer to #3213.

• This will log discord.py library logs to sys.stdout by default.
• Defaults to INFO level.
• If the LOG_DISCORD DISCORD_LOG_LEVEL env config variable is set to DEBUG, the DEBUG level logs will be logged into a file i.e. discord.log separately while still logging the INFO level to sys.stdout.
• Reorder imports and move logger stuff to top to properly initialize colorama and set text color to loggers. Otherwise the discord.py logger text would be in white. This is kinda un-pythonic (type-checker will not like this). Proper way would be creating a new file for logger classes and stuff, and do early import of that file in bot.py to initialize those. I saw the implementation in Red-DiscordBot if I remember correctly. Let me know if this should be reverted.

[Taaku18]

Hi, I made a few changes, notably:

• discord.py logs won't be logged into a separate log file, but instead the same file as the bot.
• Changed maxBytes from 48000 (48kb) to 28000000 (28mb), the previous value was only enough for 6000 characters.
• Some stylistic changes, and updated changelog.

Would be great if you can double-check my edit, and then this PR's good to go!

[Jerrie-Aries]

Looks good to me.

But I just got this error when scrolling through the pages from ?debug command.
DISCORD_LOG_LEVEL was set to Debug.

2023-07-13 16:16:33 discord.ui.view[412] - ERROR: Ignoring exception in view <PaginatorView timeout=210 children=5> for item <PageButton style=<ButtonStyle.primary: 1> url=None disabled=False label='>' emoji=None row=None>
Traceback (most recent call last):
  File "/User/Projects/modmail/.venv/lib/python3.9/site-packages/discord/ui/view.py", line 425, in _scheduled_task
    await item.callback(interaction)
  File "/User/Projects/modmail/core/paginator.py", line 285, in callback
    await interaction.response.edit_message(**kwargs, view=self.view)
  File "/User/Projects/modmail/.venv/lib/python3.9/site-packages/discord/interactions.py", line 812, in edit_message
    await adapter.create_interaction_response(
  File "/User/Projects/modmail/.venv/lib/python3.9/site-packages/discord/webhook/async_.py", line 221, in request
    raise HTTPException(response, data)
discord.errors.HTTPException: 400 Bad Request (error code: 50035): Invalid Form Body
In data.content: Must be 2000 or fewer in length.

Maybe some of the lines just have more than 2000 characters in it (single line)?

Update:
I've found the issue, it's in async def debug in cogs/utility.py. I'll just push the commit to this branch.

[Taaku18]

Everything looks good to me!