[ECS] First pass on the ECS documentation
[ECS] First pass on the ECS documentation

macobo/documentation,jhotta/documentation,inokappa/documentation,macobo/documentation,jhotta/documentation,inokappa/documentation,inokappa/documentation,jhotta/documentation,inokappa/documentation,macobo/documentation,jhotta/documentation,inokappa/documentation,jhotta/documentation,jhotta/documentation,macobo/documentation,macobo/documentation