Add integration tests against a generated project

[vierbergenlars]

To verify the correct workings of the starters, add an integration test that will build a standard generated content-cloud project.

There are no modifications done to the generated project, so it can easily be replaced with a freshly generated copy.

Instead, a build in the integration-tests folder will grab the generated project and the main project and use them as included builds.
Using included builds automatically sets up dependency substitutions for the participating projects, and in addition we set up a configurable dependency substitution for the org.springframework.boot plugin itself, so we can test against different spring boot versions.

[tgeens]

Integration tests fail because bintray (gradle plugins) is down again ?

[vierbergenlars]

They were failing because bintray was down.

Now they are failing because the AWS SDK expects a region and throws when it does not have a region.
Is that something we can look to fix in the contentcloud-spring-boot-autoconfigure project? (which gets injected by the starter too)

[tgeens]

Looks like it's a "missing feature" from the AWS SDK v2:

aws/aws-sdk-java-v2#2229 which points to aws/aws-sdk-java-v2#52
and we can conclude it's not getting fixed any time soon

So should we provide a default region ?

[vierbergenlars]

Since endpoint is configurable, we can put a bogus region in if the endpoint is set or S3 is disabled (until paulcwarren/spring-content#667 is released).
Otherwise, we can read the region from a normal spring configuration variable and put it in the aws.region system property (that is read by s3)