Removal of the helper.GetRepoPath

To break dependency on the global config.Config variable we need to refactor the code and remove functions that depend on it directly or indirectly.
This set of changes removes deprecated functions helper.GetRepoPath, helper.GetPath and alternates.PathAndEnv and replaces their usage with storage.Locator abstraction. In tests ad-hoc solution with creation of storage.Locator in place is applied as extraction of it on the upper levels will require a lot more changes in a single mr.
Most of the files changed are the test files and they are located in the first commit.

Part of: #2699 (closed)