Enhancement: Add first and last timestamp to Results Summary

[YamatoSecurity]

Add the first and last timestamps to Results Summary and HTML report:
Before:

Results Summary:

Events with hits / Total events: 19,616 / 47,465 (Data reduction: 27,849 events (58.67%))

After:

Results Summary:

First timestamp: 2022-06-01 02:55:30.738 +09:00
Last timestamp: 2022-09-25 04:53:50.748 +09:00

Events with hits / Total events: 19,616 / 47,465 (Data reduction: 27,849 events (58.67%))

I would like to print the timestamp in the same format as the other timestamps. (according to the Time Format options).

In the HTML report, output the timestamps before Results Summary and Saved alerts and events.

[hitenkoku]

@YamatoSecurity I have the following two questions.

1. First timestamp and last timestamp are the information of the detected record or all record?
2. Should the timestamp be displayed before the sparkline display?

[YamatoSecurity]

@hitenkoku

1. based on all records
2. When the sparkline timeline is displayed, let's put it after the timeline and right before Events with hits / Total events