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

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![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)

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*Sponsored by Kithara Software GmbH*

models/issues/tracked_time_test.go

@@ -115,3 +115,15 @@ func TestTotalTimesForEachUser(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Len(t, total, 2)
 }
+
+func TestGetIssueTotalTrackedTime(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	ttt, err := issues_model.GetIssueTotalTrackedTime(db.DefaultContext, &issues_model.IssuesOptions{MilestoneIDs: []int64{1}}, false)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 3682, ttt)
+
+	ttt, err = issues_model.GetIssueTotalTrackedTime(db.DefaultContext, &issues_model.IssuesOptions{MilestoneIDs: []int64{1}}, true)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 0, ttt)
+}