Add support for Elasticsearch

Add auto-configuration and starters for Elasticsearch.

Fixes gh-408
Add Elasticsearch tests

Add unit tests for elasticsearch packages. Also refactor some
of the existing tests to prevent Repository clashes.

See gh-408
Add Elasticsearch appendix links

See gh-408
Merge branch 'gh-408'
Fix broken documentation links
Restore test classes

Restore test classes accidentally deleted and ignored in c43fd04f3e.
Fixup POM errors
Create JMS sub-packages

Reorganize the `jms` package into `hornetq` and `activemq` sub-pacakges.

Fixes gh-1005
Add more enforcer rules
Fix grape -> compiler package tangle

Fix package tangle by moving DependencyResolutionContext from the
compiler package to grape.

See gh-1004
Fix CLI command/option package tangle

Fix package tangle in CLI my extracting ExitStatus to a status package.

See gh-1004
Add spring-boot-versions to the full build
Add spring-boot-versions to the prepare profile
Support for Ratpack script enhancement

@EnableRatpack is detected and triggers autoimports to
support ratpack {} DSL (handlers only, since modules are
not needed in a Spring application).
Re-order AST transformations

Now a script with *just* ratpack{} also works
(no need to explicitly @EnableRatpack)
Update for ratpack 0.9.5
Remove some compiler warnings