Contribute to event (create new page) for translations

[reshamas]

Main page: https://pymc-data-umbrella.xyz/en/latest/contributing/index.html#

Move this translation note to sub-page:
https://pymc-data-umbrella.xyz/en/latest/contributing/index.html#translating-content-volunteers-needed

Instructions

1. https://www.transifex.com/pymc/data-umbrella-sprints-website/dashboard/
2. use GitHub to log in