Make it store its internal `zap.Logger`'s level. Also, make all the
components to accept internal `logger.Logger` instead of `zap.Logger`; it
will simplify future refactor.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Implement `Controller` designed to analyze the values collected by the local
node (the source is hidden behind Writer/WriterProvider interfaces) and
transfer them to the destination (hidden behind Iterator / IteratorProvider
interface).
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>