Epoch Completed and Completed times should include handlers times

[vfdev-5]

🚀 Feature

Following discussions here: #1098 (comment) idea is to include the times spent in executing handlers attached to EPOCH_COMPLETED and COMPLETED into

ignite/ignite/engine/engine.py

Line 699 in 93e090e

self.state.times[Events.EPOCH_COMPLETED.name] = time_taken

and

ignite/ignite/engine/engine.py

Line 709 in 93e090e

self.state.times[Events.COMPLETED.name] = time_taken