bem-config: how to put config inside different directory?

To achieve this task I provide param `pathToConfig` to BemConfig()
but now levels are resolved relative to `dirname(pathToConfig)`

so then I tried to provide `cwd` still levels resolves same

Start by tracing BemConfig handling of the pathToConfig and cwd parameters, then inspect how levels are resolved relative to the configuration directory. Done means a configuration can be placed in a different directory and its levels resolve from the intended location rather than always from dirname(pathToConfig).

Written by the indexing model from the issue text.