🤩 Added devcontainer setup so contributors can use Codespaces 🤩

[jonathanagustin]

TL;DR Contributors will less likely need to worry about the environment. Adding a devcontainer will allow contributors to work with GitHub Codespaces. A cloud setup will facilitate eval contributions and will hopefully lead to a higher contribution amount.

~~I tried different images and ultimately chose miniconda as the image because it took care of problems with running Jupyter notebooks. Also, it was more lightweight and faster than other images such as universal and anaconda.~~

Edit: I switched to the Python3.9 image because I found a way to get the Jupyter extension working (I had to install the pre-release version of the Jupyter extension).

Other things to note:

• Git LFS is pre-installed
• added project-specific auto-formatting and linting
• added a welcoming message for users to safely add their API key and to be aware of API costs
• added a resource monitor extension so users can be aware of memory capacities
• added a snowflake extension
• added a jsonl extension
• GitHub Autopilot was not pre-installed because I assumed that developers who pay for it will add the extension. If you don't pay for it and use it, a bunch of error messages will appear. It might make the user experience potentially bad for a beginner that doesn't use Autopilot.

If merged, the README.md should be modified to make contributors aware of Codespaces/devcontainer development.

[jonathanagustin]

@andrew-openai

Tagging you because this PR will be buried with eval PRs and because it would be nice to have something like this sooner than later (there's a lot of messages in issues/discussions about problems with running/setup and adding a devcontainer will potentially resolve these issues).

[andrew-openai]

Thank you for the contribution, Jonathan! Very interested in getting this to work with GitHub Codespaces, I'll spend some time testing it this week, but will need to prioritize merging Eval PRs in the next few days.