refactor(auth): move startUrls to constants file

[nkomonen-amazon]

Problem

Static start urls are scattered

Solution

Move them to the auth constants file

Additional

Created a file for datetime related code. It includes static values which represent certain amounts of time in milliseconds.
Future work will use this.

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License: I confirm that my contribution is made under the terms of the Apache 2.0 license.

[justinmk3]

Future idea: Now that we have this module, maybe the datetime formatting functions should live in it

aws-toolkit-vscode/packages/core/src/shared/utilities/textUtilities.ts

Lines 349 to 374 in f98622b

	// Given number of milliseconds elapsed (ex. 4,500,000) return hr / min / sec it represents (ex. "1 hr 15 min")
	export function convertToTimeString(durationInMs: number) {
	const time = new Date(durationInMs)
	const hours = time.getUTCHours()
	const minutes = time.getUTCMinutes()
	const seconds = time.getUTCSeconds()
	let timeString = `${seconds} sec`
	if (minutes > 0) {
	timeString = `${minutes} min ${timeString}`
	}
	if (hours > 0) {
	timeString = `${hours} hr ${timeString}`
	}
	return timeString
	}
	// Given Date object, return timestamp it represents (ex. "01/01/23, 12:00 AM")
	export function convertDateToTimestamp(date: Date) {
	return date.toLocaleDateString('en-US', {
	month: '2-digit',
	day: '2-digit',
	year: '2-digit',
	hour: '2-digit',
	minute: '2-digit',
	})
	}

[nkomonen-amazon]

Good callout, yeah I agree anything datetime related should just live in this module. I've moved the time related functions from this file in a new commit.