Default time range for Event Frame trend

Set the default start time for all EF trends to be 5 minutes before the EF start time and make it configurable. Use case is attached. Root cause EF are of no value here unless the default view when you first view the event is the start time of the trend is the start time of the root cause EF. In that case, the root cause EF overrides the default start time offset mentioned above. Also format it so the user can see the start of the event on the trend. Sometimes, an EF triggers when a condition has been true for some time. We need something similar in this case as well. I really don't want to require a root cause EF for this if I only want the time offset for the trend. Then I have the baggage of the root cause EF - more SQL records, etc...