Translate markdown files

[PierreBresson]

Summary

As a user, I want to be have the entire app content available in my language.

Proposed feature

Find a way to translate markdown files with poeditor and propose a mechanism. Right now Act tab content is in english for e.g

NB1 : this is could be a large and complicated task, probably not suitable for beginners.
NB2 : due to spam, I won't assigned this task to anyone without previous contribution to this repo but PR are accepted, just have a look if there is no PR up and if this issue is not assigned to anyone.