Access Control: refactor permission evaluator to be more flexible (#35996)

* add a more flexible way to create permissions

* update interface for accesscontrol to use new eval interface

* use new eval interface

* update middleware to use new eval interface

* remove evaluator function and move metrics to service

* add tests for accesscontrol middleware

* Remove failed function from interface and update inejct to create a new
evaluator

* Change name

* Support Several sopes for a permission


* use evaluator and update fakeAccessControl

* Implement String that will return string representation of permissions
for an evaluator

Co-authored-by: Gabriel MABILLE <gamab@users.noreply.github.com>

Co-authored-by: Emil Tullstedt <emil.tullstedt@grafana.com>

pkg/services/accesscontrol/scope.go

@@ -0,0 +1,25 @@
+package accesscontrol
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Scope builds scope from parts
+// e.g. Scope("users", "*") return "users:*"
+func Scope(parts ...string) string {
+	b := strings.Builder{}
+	for i, c := range parts {
+		if i != 0 {
+			b.WriteRune(':')
+		}
+		b.WriteString(c)
+	}
+	return b.String()
+}
+
+// Parameter returns injectable scope part
+// e.g. Scope("users", Parameter(":id")) or "users:" + Parameter(":id")
+func Parameter(key string) string {
+	return fmt.Sprintf(`{{ index . "%s" }}`, key)
+}