Discord.http

- Added ability to unload cogs
- Added ability to unload extensions (which unloads all cogs within)
- Added easier fucntion to `Client` to resync commands loaded
- Removed unused code
- Polished code

- Added error for when `User` gets used instead of `Member` to a command
- Added new errors: `InvalidMember` and `Ratelimited` (User for ratelimit outside of Discord's standard response)
- Added `User.display_name` that uses `User.global_name` if available, otherwise `User.name`

- Fix consistency of the create functions
- Fix embed timestamp not working

- Added missing docstring text
- Cleaned code overall to boost performance
- Removed unused code
- Improved Python types
- Added ability to use `Permissions` for `commands.bot_has_permission`, `commands.has_permission` and `commands.default_permissions`
- Improved error output to make more sense in some places
- Fixed SubGroup not having user- and guild install kwarg, making it not sync well with subcommands

- Fixed `Guild.owner_id` not always being available in situations like `Invite`
- Added ability to make user commands with the new user install
- Added `commands.allow_contexts` to better control where commands can be used
- Reworked `commands.guild_only` to basically use `commands.allow_contexts` as an alias
- Improved `commands.default_permissions` to accept `Permissions` as a valid argument
- Added user_install to `utils.oauth_url()`

- Made `Guild.owner_id` always return `int` and not `Optional[int]`
- Added `PartialMessage.jump_url` which defaults to using `me` in the URL
- Made the logging system use `sys.stdout` to print the logs