XD-2326 - Fixed Windows file path issues

Fixed ArchiveModuleRegistry and various tests.  Some tests in
spring-xd-hadoop will not run on windows. Those are skipped if running
windows.

Fixed shell tests for Windows

* A few tests are disabled for windows.  Others work by applying
FixtureUtils.preventShellEscapeProcessing() to file paths.

* reverted DatasetOutboundChannelAdapterIntegrationTests.xml
Adding placeholder for phd21
XD-2367 Add waitForCompletion to fix failing test in CI environment
Add description for spring-xd-exec to satisfy maven central requirements
XD-2370 Removed script tests

All tests that were used by the CI build are currently handled by Acceptance Tests.
Fix classpath for SparkTasklet

 - If classloader url.getFile() contains `!/` in the path, it gets appended to the spark classpath.
 - Split file path by removing the `!/` pattern
Add Test Env. Variable; Remove Bogus Test File

Spring Integration components that create messages require
a `BeanFactory` to get access to the configured `MessageBuilderFactory`.

An environment variable `SI_FATAL_WHEN_NO_BEANFACTORY` helps developers
by treating a missing bean factory as fatal.

Spring XD (particularly in message bus implementations) programmatically
creates many SI components; we need to ensure such components get a bean
factory.

Set the environment variable when running test cases.

This has the (unfortunate) side effect of requiring a bean factory
for components created programmatically in test cases. In this case
simply inject `mock(BeanFactory.class)`.

Also remove an invalid test class from `spring-xd-hadoop`.
XD-2203 Make sure Spring XD's PDF reference doc has right release revision references

* Add `appversion` attribute under the `asciidoctorDocbook` Gradle task
* Update `asciidoctor-gradle-plugin` to `1.5.0`
* Update `docbook-reference-plugin` to `0.3.0`
* Add `compat-mode` attribute under the `asciidoctorDocbook` Gradle task
* Add `compat-mode` attribute under the `asciidoctorHtml` Gradle task