[Enhancement] Package spec should expose a flag if the integration can be run on EA standalone or not + supported outputs

[lucabelluccini]

The package spec should be enhanced to expose 2 informations:

• If the integration can be used on Elastic Agent standalone or not. Examples:
  • APM Integration Clarify that Elastic Agent standalone is not officially supported for APM usecase apm-server#6921
  • Synthetics integration https://www.elastic.co/guide/en/observability/current/synthetics-private-location.html#:~:text=Private%20Locations%20cannot%20be%20set%20up%20using%20standalone%20Elastic%20Agents
• The list of supported outputs per integration. Examples:
  • APM integration only supports Elasticsearch
  • Fleet Server integration only supports Elasticsearch
  • Synthetics (Private Locations) integration only supports Elasticsearch https://www.elastic.co/guide/en/observability/current/synthetics-private-location.html#:~:text=Private%20Locations%20running%20through%20Elastic%20Agent%20must%20have%20a%20direct%20connection%20to%20Elasticsearch
  • Elastic Defend supports Elasticsearch, Logstash, Kafka (since 8.12)

The information can be used in docs and in the future by Fleet UI in some situations.

[andrewkroh]

I'm thinking this topic should be transferred over to elastic/package-spec, WDYT @lucabelluccini?

[lucabelluccini]

I agree @andrewkroh

[lucabelluccini]

Bonus points:

• The manifest can tell if it can support custom fields