Remove/rethink all-contributors

[Saransh-cpp]

Describe the Bug

all-contributors is now unmaintained 😞

• bug: allcontributors.org not running all-contributors/all-contributors.github.io#835
• https://github.com/orgs/the-turing-way/discussions/4245

I would suggest removing the bot for now for security reasons.

To Reproduce

No response

Expected Behaviour

No response

Actual Behaviour

No response

Version In Use

NA

Additional Context

- Cookiecutter version:
- Operating system:
- Python version:

[samcunliffe]

The tail-end of the Turing Way discussion is promising.

Failing that, it's not a burden to manually maintain a list of contributors (and emoji). I've done it before. We anyway have to write sentences like "@all-contributors please add @Saransh-cpp for bug". Doesn't feel much extra work to type something similar into the README.