LPS-51819

This is an update for [LPS-51819](https://issues.liferay.com/browse/LPS-51819).<br><br>

Hey Jorge! 

Here's our first draft of the implementation.  The ticket number is a sub-task, with the second sub-task being to apply the changes to the sign-in portlet once they're approved. A few things to note:
- We added a "user.name.required.fields" property that the jsp uses to add the required validator to the form fields.
- The .getFullName method can now optionally accept two boolean arguments to include the prefix or suffix (respectively) in the display name.  If no arguments are passed, it will display neither (same as current behavior).
- We still rely on some iteration of "first-name,middle-name,last-name".  We still don't support something like "first-name,last-name,last-name" as the forms would not save correctly due to duplicate field names. One possible option could be to simply localize the middle-name to stand in as a second family name, if necessary.