Show total TrackedTime on issue/pull/milestone lists (#26672)

TODOs:
- [x] write test for `GetIssueTotalTrackedTime`
- [x] frontport kitharas template changes and make them mobile-friendly

---

![image](https://github.com/go-gitea/gitea/assets/24977596/6713da97-201f-4217-8588-4c4cec157171)

![image](https://github.com/go-gitea/gitea/assets/24977596/3a45aba8-26b5-4e6a-b97d-68bfc2bf9024)

---
*Sponsored by Kithara Software GmbH*

models/issues/issue_test.go

@@ -191,6 +191,12 @@ func TestIssues(t *testing.T) {
 			},
 			[]int64{}, // issues with **both** label 1 and 2, none of these issues matches, TODO: add more tests
 		},
+		{
+			issues_model.IssuesOptions{
+				MilestoneIDs: []int64{1},
+			},
+			[]int64{2},
+		},
 	} {
 		issues, err := issues_model.Issues(db.DefaultContext, &test.Opts)
 		assert.NoError(t, err)