Config can partially be shared between Storages

[ikopylov]

Config is a big structure. If many Storage instances are created within the application, then the config introduces a large overhead. Most of the config parameters are non-specific and can be shared between storage instances, which will reduce memory consumption.
The idea is to split the Config into specific (stores work_dir and some other parameters) and shared one and make the ability to build it with Builder. Probably, this will require to create separate Builder struct for this purpose