Replace all fmt.Errorf and errors.New in production code with
coreerr.E("caller.Method", "message", err) from go-log. Replace
all os.ReadFile/os.WriteFile/os.MkdirAll/os.Remove with coreio.Local
equivalents from go-io. Test files are intentionally untouched.
Co-Authored-By: Virgil <virgil@lethean.io>