Minor Breaking Changes in AccountService

[joeaudette]

This issue only impacts those who are subclassing the AccountService.

It has a new constructor dependency on ILdapHelper that you will need to add to the constructor of your subclass and pass to the base class constructor.

Also previously the protected members were named like private members and they have been renamed for consistency with other protected members on other classes.

For example _userManager is now UserManager, etc, same for other protected members.

These changes will result in compile time errors that you can easily fix by adding the new dependency and using the new member names.