[kbn-pm] Include Kibana's transitive _projects_ in build

[kimjoar]

I realized we already had the required info in the deps, so we don't need to rely on the kibana.build.skip field in the package.jsons. The includeTransitiveProjects helper could potentially enable some nice features as we move towards watching and stuff like that too.

Also, this makes it more obvious that only transitive projects of Kibana will are intended to work right now, as they are the only ones included when yarn is ran. Later on I think we might want to include other things in the build too, but then I think we should specifically include it through package.json instead, plus we need a solution for installing deps.

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request

[elasticmachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request

[kimjoar]

@spalger Rebased and updated

[spalger]

This works and skips the eslint stuff without needing config in each package, which is a good step, but could be improved in a future PR.

In the new build process we'll have multiple package.json files, one in each build output, and each will define slightly different projects necessary for the build. If buildProductionProjects() knew this it could read the package.json from the build output and only build the projects necessary for that build.

Even further, it could know that there are multiple build targets and only run each build step once and copy the output to each build target that needs it.

Alternatively, we can go back to the bulk of this being implemented in the build tasks and expose an API for the build tasks to get project info/graphs so it can do just the work it needs.

Like I said, we can do all this in subsequent prs if you like any of it.

[kimjoar]

Great input, @spalger. I like the idea of extracting build_production_projects.ts into the build tasks, and keeping @kbn/pm focused on the projects themselves, including exposing functions like includeTransitiveProjects.