Cherry-pick #16586 to 7.x: Add cloudfoundry input for filebeat

[blakerouse]

Cherry-pick of PR #16586 to 7.x branch. Original message:

What does this PR do?

Add cloudfoundry input to x-pack filebeat.

Why is it important?

To support Cloud Foundry.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works

Author's Checklist

• Sends http access, log messages, and error logs to elasticsearch.

How to test this PR locally

Run x-pack build of filebeat with the following configuration, with a deploy cloudfoundry. Substitute the configuration variables based on the cloudfoundry deployment and authentication.

filebeat.inputs:
  - type: cloudfoundry
    api_address: https://api.dev.cfdev.sh
    client_id: firehose-to-filebeat
    client_secret: verysecret
    ssl:
      verification_mode: none

output.console:
  pretty: true

Related issues

• Relates [Meta] Cloud Foundry Support #16520

Use cases

Screenshots

Logs

[blakerouse]

I forgot the changelog entry in the original PR, I have a follow up PR that has the changelog for this change.

[ChrsMark]

lgtm