Remove references to Tabula theme and start porting essential components

[znat]

Proposed changes: Exploratory changes to remove the Tabula theme from the docs while preserving mdx functionality such as playground and chat bubbles.

Status (please check what you already did):

• [ ] added some tests for the functionality
• [ ] updated the documentation
• [ ] updated the changelog (please check changelog for instructions)
• [ ] reformat files using black (please check Readme for instructions)