Cleanup work

Remove User POCO and switch to using shared IdentityUser for EF
Rename claimstype options to ClaimsIdentityOptions
Cleanup overloads for IdentityBuilder
Yeah this was a bit weird, but basically this typically is using the Options that the SignInManager passes in, which itself uses the options off of the UserManager.  It could also get an instance of the Options itself, but currently it just reuses the instance off the user manager.