Allow programmatically writing cookies during a session

[lukasmasuch]

Checklist

• I have searched the existing issues for similar feature requests.
• I added a descriptive title and summary to this issue.

Summary

Provide a native API that allows writing and reading cookies during a user session.

Why?

No response

How?

Provide st.cookies or st.context.cookies as a writable dict that syncs the cookies with the user browser of a given session.

Draft spec

Additional Context

• Related issue: Ability to write cookies #861
• Available extra: https://extras.streamlit.app/?extra=%F0%9F%8D%AA+Cookie+Manager

[github-actions]

To help Streamlit prioritize this feature, react with a 👍 (thumbs up emoji) to the initial post.

Your vote helps us identify which enhancements matter most to our users.