dev/event#9 Event Templates: do not set the Start/End dates

[mlutfy]

Overview

When creating an event using an event template, the Start Date is automatically set to the date when the template was created.

To reproduce:

• Create an Event Template (Administer > Events > Event Templates)
• Wait one day, or set the start_date to some past date (templates are saved as regular events in the civicrm_event database table).
• Create a new Event, and use the template that was created.
• Notice how the start date is automatically set.

This might not sound like a big deal, but when the event template was created in 2015, it gets pretty annoying to have to also click to change the year (and it's easy to overlook).

This was also reported on Stack Exchange:
https://civicrm.stackexchange.com/questions/28159/event-template-start-date

Gitlab issue: https://lab.civicrm.org/dev/event/issues/9

Before

Start Date is automatically set to some old date in the past.

After

Start Date is not set.

Technical Details

I also unset end_date as a precaution. It should not be set, but if someone created a template from an existing event, it could.

[civibot]

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[mattwire]

Reviewed and tested by @lcdservices here https://lab.civicrm.org/dev/event/issues/9#note_20934 I've tested and approve this change.