Lower technical requirements for new contributors

As part of our roadmap, we want to make easier for people to join in order to grow the number of contributors and add some heterogeneity.

Document things without Git, OpenGPG, have translation platform etc

Team: mercedes508, sajolida

Original created by @mercedes508 on 14516 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information