Add endpoint.spec that renders the endpoint program to be run by Agent

[blakerouse]

What does this PR do?

Adds the spec/endpoint.yml that parses the elastic-agent.yml into a configuration that is passed to Endpoint. This passes the entire input definition into the Endpoint configuration, allowing Agent not need need to worry about new keys. Fleet and output is also passed through directly to Endpoint.

This does not include the code to actually perform the installation of Endpoint and run it, this is just step 1 of that process. Next branch will perform the installation, now that this branch instructs Elastic Agent that Endpoint should be ran.

Why is it important?

To support Elastic Agent running Endpoint.

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
• [ ] I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Author's Checklist

• Results in a Endpoint Configuration:

fleet:
  kibana_url: https://kibana.mydomain.com:5601
  ca_hash: 7HIpactkIAq2Y49orFOOQKurWxmmSFZhBCoQYcRhJ3Y=
  checkin_interval: 5m

output:
  elasticsearch:
    hosts: [127.0.0.1:9200, 127.0.0.1:9300]
    username: elastic
    password: changeme
    api_key: TiNAGG4BaaMdaH1tRfuU:KnR6yE41RrSowb0kQ0HWoA
    ca_sha256: 7HIpactkIAq2Y49orFOOQKurWxmmSFZhBCoQYcRhJ3Y=

type: endpoint
enabled: true
streams: []
policy:
  linux:
    malware:
      mode: prevent
    advanced:
      elasticsearch:
        indices:
          logging: logging-index
          control: control-index
          event: event-index
        kernel:
          process: true
          connect: true
    logging:
      file: info
      stdout: debug
    events:
      registry: true
      process: true
      security: true
      file: true
      dns: false
      dll_and_driver_load: false
      network: true
  windows:
    malware:
      mode: prevent
    advanced:
      elasticsearch:
        indices:
          logging: logging-index
          control: control-index
          event: event-index
        kernel:
          process: true
          connect: true
    logging:
      file: info
      stdout: debug
    events:
      registry: true
      process: true
      security: true
      file: true
      dns: false
      dll_and_driver_load: false
      network: true
  mac:
    malware:
      mode: prevent
    advanced:
      elasticsearch:
        indices:
          logging: logging-index
          control: control-index
          event: event-index
        kernel:
          process: true
          connect: true
    logging:
      file: info
      stdout: debug
    events:
      registry: true
      process: true
      security: true
      file: true
      dns: false
      dll_and_driver_load: false
      network: true

How to test this PR locally

Related issues

• Closes [Elastic Agent] Limit Endpoint usage #19130

Use cases

Screenshots

Logs

[elasticmachine]

Pinging @elastic/ingest-management (Team:Ingest Management)

[elasticmachine]

💚 Build Succeeded

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Build stats

• Build Cause: [Pull request #19171 updated]

• Start Time: 2020-06-18T13:38:49.222+0000

• Duration: 33 min 23 sec

Test stats 🧪

Test	Results
Failed	0
Passed	538
Skipped	127
Total	665

[blakerouse]

Converted to draft until the final endpoint configuration that Elastic Agent will send is complete.

[ph]

LGTM