Adding SecurityEnabled to PSADGroup, updating help documents, and …

[j82w]

…only allowing security enabled groups to be set for Azure SQL Server Active Directory Administrator.

[azurecla]

Hi @j82w, I'm your friendly neighborhood Azure Pull Request Bot (You can call me AZPRBOT). Thanks for your contribution!

It looks like you're working at Microsoft (jawilley). If you're full-time, we DON'T require a contribution license agreement.

If you are a vendor, or work for Microsoft Open Technologies, DO please sign the electronic contribution license agreement. It will take 2 minutes and there's no faxing! https://cla.azure.com.

TTYL, AZPRBOT;