CloudWatch: fix custom namespace for listing dimension keys, refactor to non-pointer types, add test assertions, rename packages (#59106)

Co-authored-by: Erik Sundell <erik.sundell87@gmail.com>

pkg/tsdb/cloudwatch/models/resources/dimension_keys_request.go

@@ -0,0 +1,50 @@
+package resources
+
+import (
+	"net/url"
+)
+
+type DimensionKeysRequestType uint32
+
+const (
+	StandardDimensionKeysRequest DimensionKeysRequestType = iota
+	FilterDimensionKeysRequest
+)
+
+type DimensionKeysRequest struct {
+	*ResourceRequest
+	Namespace       string
+	MetricName      string
+	DimensionFilter []*Dimension
+}
+
+func (q *DimensionKeysRequest) Type() DimensionKeysRequestType {
+	if isCustomNamespace(q.Namespace) || len(q.DimensionFilter) > 0 {
+		return FilterDimensionKeysRequest
+	}
+
+	return StandardDimensionKeysRequest
+}
+
+func GetDimensionKeysRequest(parameters url.Values) (DimensionKeysRequest, error) {
+	resourceRequest, err := getResourceRequest(parameters)
+	if err != nil {
+		return DimensionKeysRequest{}, err
+	}
+
+	request := DimensionKeysRequest{
+		ResourceRequest: resourceRequest,
+		Namespace:       parameters.Get("namespace"),
+		MetricName:      parameters.Get("metricName"),
+		DimensionFilter: []*Dimension{},
+	}
+
+	dimensions, err := parseDimensionFilter(parameters.Get("dimensionFilters"))
+	if err != nil {
+		return DimensionKeysRequest{}, err
+	}
+
+	request.DimensionFilter = dimensions
+
+	return request, nil
+}