* Add integration tests for /error view
* Add "error" @Bean as default view for HTML
Users may see side effects because now there will be
a ContentNegotiatingViewResolver by default for the
first time in a vanilla Actuator app. Should be
interesting.
[Fixes#54597932] [bs-273] Circular view reference for /error
Rework main build POM to be an aggregator pom that does not inherit
from any parent. Introduce new spring-boot-dependencies module to
act as a parent for both spring-boot-starter-parent and
spring-boot-parent.