Prometheus: Introduce prometheus backend library (#83952)

* Move files to prometheus-library

* refactor core prometheus to use prometheus-library

* modify client transport options

* mock

* have a type

* import aliases

* rename

* call the right method

* remove unrelated test from the library

* update codeowners

* go work sync

* update go.work.sum

* make swagger-clean && make openapi3-gen

* add promlib to makefile

* remove clilogger

* Export the function

* update unit test

* add prometheus_test.go

* fix mock type

* use mapUtil from grafana-plugin-sdk-go

pkg/promlib/models/scope.go

@@ -0,0 +1,52 @@
+package models
+
+import (
+	"github.com/prometheus/prometheus/model/labels"
+	"github.com/prometheus/prometheus/promql/parser"
+)
+
+func ApplyQueryScope(rawExpr string, matchers []*labels.Matcher) (string, error) {
+	expr, err := parser.ParseExpr(rawExpr)
+	if err != nil {
+		return "", err
+	}
+
+	matcherNamesToIdx := make(map[string]int, len(matchers))
+	for i, matcher := range matchers {
+		if matcher == nil {
+			continue
+		}
+		matcherNamesToIdx[matcher.Name] = i
+	}
+
+	parser.Inspect(expr, func(node parser.Node, nodes []parser.Node) error {
+		switch v := node.(type) {
+		case *parser.VectorSelector:
+			found := make([]bool, len(matchers))
+			for _, matcher := range v.LabelMatchers {
+				if matcher == nil || matcher.Name == "__name__" { // const prob
+					continue
+				}
+				if _, ok := matcherNamesToIdx[matcher.Name]; ok {
+					found[matcherNamesToIdx[matcher.Name]] = true
+					newM := matchers[matcherNamesToIdx[matcher.Name]]
+					matcher.Name = newM.Name
+					matcher.Type = newM.Type
+					matcher.Value = newM.Value
+				}
+			}
+			for i, f := range found {
+				if f {
+					continue
+				}
+				v.LabelMatchers = append(v.LabelMatchers, matchers[i])
+			}
+
+			return nil
+
+		default:
+			return nil
+		}
+	})
+	return expr.String(), nil
+}