Powermock does not support JUnit5 yet, so we need to remove it
to support JUnit 5. Additionally, maintaining additional libraries
adds extra work for the team.
Mockito now supports final classes and static method mocking. This
commit replaces Powermock with mockito-inline.
Closes gh-6025
As of Spring 4.3 RC1 the `org.aopalliance` interfaces are once again bundled
with `spring-aop` [1]. Moreover, all modules with a dependency on
`aopalliance:aopalliance` directly or indirectly also depend on `spring-aop`.
This change drops the `aopalliance:aopalliance` dependency in all places it's
declared. Where applicable an explicit dependency on `spring-aop` was added in
its place. (This dependency was already present in most places; in one case the
module didn't require `aopalliance:aopalliance` in the first place.)
The documentation is updated accordingly.
[1] https://jira.spring.io/browse/SPR-13984