Show reason of failure in case of deployment error

* Display information about up to 3 last failed events,
  including the reason of failure
* Add the Reason column to the log table of Heat stack events

Closes-Bug: #1288195
Partially implements: blueprint tripleo-deployment-failed-page

Change-Id: I18c6b90f21dce85ab3114cb1fb8f73422659cb03
Merge "Show reason of failure in case of deployment error"