[201] Add specification for creation, deletion, reconnection, DnD and labels...

[201] Add specifications for creation, deletion, reconnection, DnD and labels for all elements of each diagrams.

Each diagram is described using a separated asciidoc file and can be access inside the platform using help button: Help -> Diagram Specification -> Class diagram specification

Bug: #201 Signed-off-by: Aurelien Didier aurelien.didier51@gmail.com