Manage additional files

[mbrannigan]

What does this PR do?

This PR adds an additional section in pillar to produce additional config files in /etc/datadog-agent. You include the contents of these yaml files into the datadog:additional_config pillar and salt will serialize that pillar data into the appropriate file.

Motivation

I need to manage system-probe.yaml as well as security-agent.yaml in the /etc/datadog-agent directory and the formula didn't have a facility to do this.

Additional Notes

Describe your test plan

If you have the additional_config pillar structured like the below example, the formula will create /etc/datadog-agent/system-probe.yaml with the specified settings in place.

datadog:
  config:
    api_key: aaaaaaaabbbbbbbbccccccccdddddddd
    site: datadoghq.com
    python_version: 2
  additional_config:
    system-probe.yaml:
      network_config:
        enabled: false
      runtime_security_config:
        enabled: true
      fim_enabled: true
      remote_configuration:
        enabled: true
      custom_sensitive_words:
        - 'personal_key'
        - '*token'
        - 'sql*'
        - '*pass*d*'