Add DateOnlyExtensions and add unit tests for the calculations

[rmaffitsancsoft]

• [x] Add new DateOnlyExtensions.cs class in the HQ.Abstractions project root
• [x] Implement the methods below (You may need to add a new Period enum value for Week)
• [ ] Update the GenerateWeeklyProjectStatusReport method to use the new extension methods
• [x] Add unit tests to HQ.Tests project that validate the calculations
  • [ ] Week period
  • [ ] Month period
  • [ ] Quarter period
  • [ ] Year period

For example, I would expect the following to be true based on recent changes to the week calculations when generating PSRs:

var today = new DateOnly(2024, 6, 12);
var weekStart = today.GetPeriodStartDate(Period.Week);
var weekEnd = today.GetPeriodStartDate(Period.Week);

// The following should be true and validated in a test, week should calculate Saturday - Friday
weekStart == new DateOnly(2024, 6, 8)
weekEnd == new DateOnly(2024, 6, 14)

public static DateOnly GetPeriodStartDate(this DateOnly forDate, Period period)
{
  // switch on period
}

public static DateOnly GetPeriodEndDate(this DateOnly forDate, Period period)
{
  // switch on period
}

[rmaffitsancsoft]

https://xunit.net/docs/getting-started/netcore/cmdline

We may be able to use [InlineData] to pass our date/expected start/expected end values to ease the use. We should have a couple test cases per period that test:

1. If forDate is on the start of the period
2. If forDate is somewhere in the middle of the period
3. If forDate is on the end of the period

[rmaffitsancsoft]

[rmaffitsancsoft]

https://nodatime.org/