[Change Proposal] Add new field for dependency on stack capabilities

[jsoriano]

There are some packages that are only useful if certain Elastic features are available. Some of these features are not going to be available in all the serverless offerings, according to these configurations. Packages requiring these features are going to need to declare it.

Add a new field for dependencies on stack capabilities. We can try to add them as a new condition:

conditions:
  kibana.version: '^8.10.0'
  elastic.subscription: 'basic'
  elastic.capabilities:
    - apm
    - uptime

But so far we don't have lists in conditions. If this is a problem, we can use comma-separated lists:

  elastic.capabilities: 'apm,uptime'

Or add a completely new field stack_capabilties.

We need to confirm the final list of capabilities, but so far we can start with:

• apm
• uptime
• enterprise_search
• serverless_search
• observability
• logs_ui
• serverless (TBD, for packages intended only for serverless)
• ilm/dlm (TBD, only if there are packages that only work with one of the lifecycle managers)