[$50] Update start date / end date values for phases to be a single control

[jmgasper]

In an effort to make the UI for phase management a bit more user friendly, I'm hoping we can consolidate the start date / time and end date / time (#1319) into single controls, instead of splitting the date and time out. There are available controls that do this, like: https://www.jqueryscript.net/time-clock/Date-Time-Picker-Bootstrap-4.html

I'm open to suggestions if one seems like it would be a good fit

[phead198708]

Challenge https://www.topcoder.com/challenges/8159a9cb-aaf0-439c-9007-cf6f6544a5b0 has been created for this ticket.

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[phead198708]

Challenge https://www.topcoder.com/challenges/8159a9cb-aaf0-439c-9007-cf6f6544a5b0 has been assigned to nursoltan-s.

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[nursoltan-s]

PR: #1321

[jmgasper]

Looks good!

[maxceem]

Payment task has been updated: https://www.topcoder.com/challenges/8159a9cb-aaf0-439c-9007-cf6f6544a5b0
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Winner: nursoltan-s
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[sdgun]

Verified in production.`