This commit creates a UserBuilder and updates samples to use it. We do not
leverate it for JdbcUserDetailsManager because it requires the schema to
be created which is difficult with a single bean definition and
unpredicatble ordering. For this, it is still advised to use
AuthenticationManagerBuilder
Fixes gh-4095
Spring 5 removed support for Tiles 2 and Thymeleaf does not support
Tiles 3 yet. This commit updates to Thymeleaf 3.0.2 and uses
Thymeleaf's build in layout support.
Issue gh-4080