fix(pkg/config): use storage endpoints

changes:
- Only one storage endpoint can be defined. This consists of a URL which
  can be used to specify whether the data is to be stored in a file or
  in a database.

pkg/internal/collect/measuredValues.go

@@ -4,13 +4,13 @@ import (
 	"github.com/go-flucky/flucky/pkg/types"
 )
 
-func MeasuredValues(measuredValuesChannel <-chan []*types.MeasuredValue) []*types.MeasuredValue {
+func MeasuredValues(measuredValueChannel <-chan *types.MeasuredValue) []*types.MeasuredValue {
 	cachedMeasuredValues := make([]*types.MeasuredValue, 0)
 	for {
 		select {
-		case measuredValues, more := <-measuredValuesChannel:
+		case measuredValue, more := <-measuredValueChannel:
 			if more {
-				cachedMeasuredValues = append(cachedMeasuredValues, measuredValues...)
+				cachedMeasuredValues = append(cachedMeasuredValues, measuredValue)
 				continue
 			}
 		default: