local: Split local ct creation and linking it to the session

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
ses: Unify ct->ses linkage for different session types

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
ses: Unify containers unlinkage from session on destroy/session close

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>