Documentation: Create README.md file for src/t8_data #1873
Description
Feature request
Subissue of #1872
Is your feature request related to a problem? Please describe.
Add a README.md file to the t8_data folder.
Describe the solution or feature you'd like
A README.md file in the t8_data folder following the description given in #1872
Describe alternatives you've considered
Estimated priority
"Priority: medium" Should be solved within half a year
Additional context
See https://github.com/DLR-AMR/t8code/tree/main/src/t8_cmesh/README.md as an example.