[Meta][Feature] Refactor how Elastic Agent know how to run a binary.

[ph]

Our spec defines how software is run by the Elastic Agent and what transformation the transpiler needs to execute to convert the configuration from an Agent configuration to a beats configuration. Change are required for the Elastic Agent to understand what is a shipper.

We would like to make the following changes.

• Allow the Specification to ship with the binaries instead of embedding it.
• Investigate how Elastic Agent could trust the file.
• Investigate how Elastic Agent could trust the binary
• Document the fields in the file.
• Validate the different fields of the file. (json schema or golang struct)
  • If field is not present we should fails.
• Allow the file to support multiple entrypoint (process filestream, process tcp)

[ph]

I've moved this comment to an actual proposal, when accepted will add it back to this issue.

[ph]

After discussing with @blakerouse we are looking at proposal 2, I am going to redo the above to make it more clearer and send it for review.

[ph]

I've sent the proposal to review, and will update this issue with the conclusion.

[ph]

This the above work was done in the v2 specification proposal and in the feature-v2-arch branch.