feat: Allow users to run one command to install both packages for speedup and voice support

[catdogmat]

Summary

This PR allows users to run one command to install both packages for speedup and voice support, eg:
python3 -m pip install py-cord[all]

Information

• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters). (kinda, it adds a new install method)
• This PR is a breaking change (e.g. methods or parameters removed/renamed).
• This PR is not a code change (e.g. documentation, README, typehinting,
  examples, ...). (kinda, it updates docs and pyproject)

Checklist

• I have searched the open pull requests for duplicates.
• If code changes were made then they have been tested.
• I have updated the documentation to reflect the changes.
• If type: ignore comments were used, a comment is also left explaining why.
• I have updated the changelog to include these changes.

[catdogmat]

Closing as I think I broke something

[catdogmat]

Ok fixed

[catdogmat]

Fixing title

[catdogmat]

Sorry if this is bad, I'm new to big repos

[Lulalaby]

Thanks for your contribution. In my opinion this isn't really needed tho.
We'll discuss that.

[Lulalaby]

We're not gonna accept this PR at this point.
Thank you tho

[VincentRPS]

Is pycord[speed,voice]=a.b.c just too much? I don't think there is any worth in adding a shortcut to what is already so simple. Maybe in the future, if we get more extra dependencies, but at the moment, two is not enough.