Add example for openshift deployment

Fixes gh-668 (if the asciicdoc compiles)
Check for existence of ResourceBundle before creating MessageSource

Irritatingly a ResourceBundleMessageSource never gives up trying to
create a resource bundle for every message resolution, so to stop
it logging all those warnings (and probably sucking performance-wise)
we need to disable the MessageSource if a bundle is not provided.

Fixes gh-1019
Initialize DependencyResolutionContext with default dependency mgmt

In the absence of a @GrabMetadata annotation,
DependencyResolutionContext provided no dependency management. This
was leading to incorrect dependency versions being pulled in. This
commit intializes the context with default dependency management that
will be replaced should @GrabMetadata be encountered.

Fixes #1021
Update dependencies to latest maintenance releases

Despite Javassist 3.18.2-GA being available, it has not be upgraded.
This is to keep it in sync with Hibernate.
Make ElasticSearchAutoConfiguration conditional on SD Elasticsearch

ElasticSearchAutoConfiguration depends on two Spring Data Elasticsearch
classes (TransportClientFactoryBean and NodeClientFactoryBean), however
it’s only conditional on Elasticsearch itself being on the classpath.
This lead to start up failures due to a ClassNotFoundException. Its
@ConditionalOnClass configuration has been updated so that the
auto-configuration will only be enabled if both Elasticsearch and Spring
Data Elasticsearch are on the classpath.

The dependencies on TransportClientFactoryBean and NodeClientFactoryBean
were ‘hidden’ in ElasticsearchProperties. The logic that uses these
types has been moved into ElasticSearchAutoConfiguration so that the
usage of the types and the related @ConditionalOnClass configuration
is in the same file.

Fixes #1023
Revert deferred DDL changes and re-oreder database migrations

Schema initialization now happens in @PostConstruct (effectively)
whether it is via the Hibernate EntityManagerFactory or the
Boot DataSourceInitialization (in addition or instead). The data.sql
script if it exists is still executed on an event fired from the
other places, so those tests are passing.

Flyway and liquibase have bean factory post processors (like
the one they use to order the audit aspect in Spring Data) that
enforce a dependency on those components from the EntityManagerFactory.
So Hibernate validation is still happy (and there are 2 tests to
prove it now as well).

Fixes gh-1022
Add missing entries to the tables of auto-configuration classes

Closes #998
Cross link Actuator and User Guide docs

Not having READMEs in github is a mistake IMO, so here's one
restored and with a link to the docs. Docs also updated to
more accurately reflect the location of the actuator features
in implementation.

See https://github.com/spring-guides/gs-actuator-service/pull/7
for the Getting started guide change

Fixes gh-1014
Add documentation for JMS support

This commit documents Boot's JMS support, in particular how Boot
can auto-configure the ConnectionFactory for ActiveMQ and
HornetQ.

Fixes gh-1026