Upgrade to SLF4J 1.7.28, Groovy 2.5.8, RxJava 2.2.12, Joda-Time 2.10.4, Rome 1.12.2, OkHttp 3.14.3, Apache HttpClient 4.5.10, Apache Johnzon 1.1.13

Includes JAX-WS 2.3.1, Awaitility 3.1.3, OkHttp 3.12, Woodstox 5.2.

Issue: SPR-17446

This commit introduces a dependency on the Awaitility assertion
framework and makes use of asynchronous assertions in order to make
tests for asynchronous events more robust.

Issue: SPR-17211

Includes upgrade to Hibernate ORM 5.3.5, EclipseLink 2.7.3, Selenium HtmlUnit Driver 2.32.1, Jetty 9.4.12 RC2.

After the Groovy 2.5 upgrade, the Spring Framework build on JDK9 hit
GROOVY-8631. Adding the relevant `jax-api` dependency to the module
didn't fix this issue. The Groovy release notes mention the use of the
`--add-modules` JVM flag, but this is not an option for this build which
should run on JDK8 -> JDK11.

This commit changes the dependency from `groovy-all` to more focused
dependencies on Groovy in the `spring-beans` and `spring-context`
modules. This change seems to avoid the automatic loading of Groovy
enhancements to JAXB (shipped with `groovy-xml`).

See:

* http://groovy-lang.org/releasenotes/groovy-2.5.html#Groovy2.5releasenotes-Knownissues
* https://issues.apache.org/jira/browse/GROOVY-8631

Issue: SPR-15407

Includes fixes for invalid exception declarations in Mockito-based unit tests. Also includes FreeMarker 2.3.27, Commons Pool 2.4.3, JSON-P 1.1.2.

Issue: SPR-16157

Issue: SPR-15974

Issue: SPR-15974

Upgrade to JAXB 2.3, JAX-WS 2.3, Annotations 1.3.1, Interceptor 1.2.1.
Also includes Log4J 2.9.1 and Asciidoctor 1.5.6.

Latest dependency updates (POI 3.17, Rome 1.8, EhCache 3.4, Caffeine 2.5.6, RxJava 2.1.4, Tomcat 8.5.21, JRuby 9.1.13, Rhino 1.7.7.2)

This reverts commit 3e2f6c84.

The main `build.gradle` file contains now only the common build
infrastructure; all module-specific build configurations have
been moved to their own build file.

Issue: SPR-15885