Fixed a few issues with the spring start script, mainly around symlinks.
Test on OSX, Ubuntu and Windows (Cygwin) with and would symlinks.

# By Oliver Gierke
* pull9:
  Cleanups Spring Data JPA example.

Various cleanups to the Spring Data JPA example, including:

* Move repositories into service package and make them package private
  thus only expose the service interfaces to clients.
* Merge HotelRepository and HotelSummaryRepository and make service
  implementations package protected.
* Introduce integration test base class to bootstrap the app as
  SpringAppliation.run would.
* Refactor central test case to rather use Spring MVC integration
  testing framework.
* Add integration tests for repositories to execute query methods.

Rework main build POM to be an aggregator pom that does not inherit
from any parent. Introduce new spring-boot-dependencies module to
act as a parent for both spring-boot-starter-parent and
spring-boot-parent.

Update ConfigFileApplicationContextInitializer so that the names
property defaults to `${spring.config.name},application`. This allows
application.properties files to be loaded even when property placeholder
expansion is not enabled.

Issue: #54462910

Issue: #54462302

Update Javadoc to indicate the sources are used in addition to those
specified on construction. Also renamed member variables and fixed
log output.

Issue: #54185750

Now the environment overrides aare **added** to the
sources provided in SpringApplication.run(). This
avoids some potential surprises where setSources()
would have been silently ignored.

[#54185750]

Turns out the maven-plugin still causes issues.

This reverts commit 1ccdf2f6.

Remove no longer required integration tests project. Samples can
now be called as part of the build since the maven plugin is no
longer an extension.

Issue: #54393078

(Might remove this later but getting ready for a release)

The problem this change fixes is that spring.main.sources would always
be bound to SpringApplication.sources when provided in a properties file
even if SpringApplication.run() is called directly with sources. This
led to confusion with users saying that their sources were not working
where in fact they weren't even being used.

There would be more than one way to approach this problem, but we
have chosen for now to ignore spring.main.sources completely
if the SpringApplication constructor was already called with
explicit non-empty sources. It might be preferable, if possible,
to only ignore its value in an external properties file (allowing
command line or System properties to override). If we want to change
the behaviour again, I suggest a new story should be created.

[Fixes #54185750] [bs-255]

* Added additional search in
AbstractEmbeddedServletContainerFactory.getValidDocumentRoot() to
detect a /WEB-INF/ directory in the code archive
* If the code archive is in /WEB-INF/** then we assume it is
safe to serve content from / (exposes the loader classes
but nothing sensitive from the app)

[Fixes #54345578]