doc(structure_of_code): import from main repo
First pull-request on this repo for me Two months ago, I created this pull-request on main Mobilizon repository : framasoft/mobilizon!1473 (merged)
Because of legitimate remarks from @tcit , I propose this PR to introduce the same content from main documentation.
I am not so happy to copy the main document from Mobilizon code and so cut the link. We should be attentive to synchronize the two files, but I do not see an easy way to make that automated and secure.
If you see other way, I will be happy to read it !