[connection] give access to session execute from connection This allows multiple function that both requires an execute method and are required by the execute method.

[connection] move last part of undo logic in connection Now that Connection have a reference to the repo it can handle all of it itself

[connection] initialize connection.user and connection.lang A RequestSessionBase need a user and lang. For now we use the session ones. Later the Connection will have it's own.

[Connection] inherit from RequestSessionBase This contains a lot method. We need them to move more code from Session to connection.