Restore: Map account properties from DTO

* Copy the new account properties from the ModifyAccountDTO
object. For some reason, the transaction rollback exceptions
are no longer being thrown

* Update the dateModified property in the Account model
each time an account is updated

* Throw Forbidden exception if the authenticating user is
not the owner of the account being modified
Implement change password

* Added a currentPassword property to ModifyAccountDTO
which is populated with the current password during a change password
operation.