Add integration tests for Cloud Foundry

[blakerouse]

For the goal of getting Cloud Foundry to GA we need to add integration tests. The best option in the case is to use CFDev to bring up a development Cloud Foundry cluster. This will bring enough up to allow apps to be deployed and for filebeat and metricbeat to connect to loggregator.

Checks can be added to ensure that:

• Container metrics are being retrieved
• Application logs are being retrieved
• Router logs are being retrieved

To verify that router logs are being retrieved an application would need to be deployed and some traffic generated to ensure that proper router logs are being retrieved.

[elasticmachine]

Pinging @elastic/integrations-platforms (Team:Platforms)

[botelastic]

Hi! We just realized that we haven't looked into this issue in a while. We're sorry! We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1. Thank you for your contribution!