The IdentityManager interface to be implemented by an identity manager implementation providing user verification and
identity loading to Undertow.
Note: The IdentityManager interface is very much work in progress, methods are added to cover use cases as identified and
then simplified as common cases are defined.
Verify a previously authenticated account.
Typical checks could be along the lines of verifying that the account is not now locked or that the password has not been
reset since last verified, also this provides an opportunity for roles to be re-loaded if membership information has
Perform verification when all we have is the Credential, in this case the IdentityManager is also responsible for mapping the Credential to an account.
The most common scenario for this would be mapping an X509Certificate to the user it is associated with.