Find a better way to determine last status change

[srijeet0406]

What does this PR (Pull Request) do?

• This PR fixes New TO server field: LastStatusChange #1636

Which Traffic Control components are affected by this PR?

• CDN in a Box
• Traffic Ops
• Traffic Portal
• CI tests

What is the best way to verify this PR?

Run local TO and TP and create a server. Notice that the status_last_updated field gets set to the current time in the DB.
Now, go to TP, and select the Status Last Updated as one of the display columns for the servers table. Notice that it shows the correct time elapsed since you created the server.
Now, update this server changing any field, EXCEPT the status of the server. Notice that the status_last_updated value DOES NOT change.
Now, update the server by changing the server's status (you will have to do this from the backend call, since TP doesn't let you do it from the front end).
Notice that the status_last_updated time gets changed to the current time this time around.

Also, make sure unit tests and API tests pass.

If this is a bug fix, what versions of Traffic Control are affected?

• master

The following criteria are ALL met by this PR

• This PR includes tests OR
• This PR does not include documentation
• This PR includes an update to CHANGELOG.md
• This PR includes any and all required license headers
• This PR ensures that database migration sequence is correct
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

Additional Information

[mitchell852]

sorry, conflict in our favorite file :)

[srijeet0406]

@mitchell852 fixed 👍

[mitchell852]

for some reason the column filter is not working in TP on this field:

I have a server i just changed the status of and it's not showing up. So i'm wondering if the data format needs to be changed to that of LastUpdated:

lastUpdated: "2020-08-28 20:53:55+00",
statusLastUpdated: "2020-08-28T20:53:55.75928Z"

I'm not sure if that will solve the TP grid problem but maybe consistent is better anyhow?

[ocket8888]

The data will compare properly if you coerce it to a Date. If you look in the servers table controller, when I set $scope.servers I map the returned servers array and apply a conversion to Date objects on the Last Updated field. So no, it's not that the Last Updated format works (in fact it's worse than the statusLastUpdated field, I had to do some string manipulation to get the Date constructor to work), it's just that it can only filter Dates by date.

[srijeet0406]

Resolved in 97bca2f

[mitchell852]

Can you update dateCellFormatter as well to this?

	/**
	 * Formats the contents of the 'lastUpdated' and 'statusLastUpdated' column cells as "relative to now".
	 */
	function dateCellFormatter(params) {
		return params.value ? dateUtils.getRelativeTime(params.value) : params.value;
	}

so dateUtils.getRelativeTime doesn't try to parse a null which displays "Invalid Date"

[mitchell852]

lgtm. all tests pass. verified manually as well. all requested changes have been made.