After the refactor there are new storage characteristics: a type and
a general storage id (that could be stringified).
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
There is a need to keep track of each local storage change. Log messages are
the most convenient way to do it.
Implement function which writes log message about the completed writing
operation in storage engine.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
