KF5: Add hover-tooltip to the labels of BasicListItem
cherry picked from !878 (merged)
Added one more commit to fix tests on Qt 5 due to simpler signature of TestCase::mouseMove method — it didn't have default values for x and y.
cherry picked from !878 (merged)
Added one more commit to fix tests on Qt 5 due to simpler signature of TestCase::mouseMove method — it didn't have default values for x and y.