Initial visualizations plugin.

[lukeelmers]

Introduces the initial visualizations plugin which will serve as the home for any vis-specific infrastructure required to power visualization development. This initial PR covers items that are currently exported by ui/vis.

Next I will need to do ui/visualize and ui/vislib. To keep this PR to a manageable size, I'd like to merge what we have first, then go back to add more services in subsequent PRs.

This initial PR includes 3 main items (easiest to review commit-by-commit):

1. Adds base plugin framework and vis types service 74c31fb
2. Moves ui/utils/brush_event to vis_filters (I discovered that's the only place it gets consumed, so thought it best to move in this PR while creating the vis filters service) 2c649a4
3. Adds vis filters service 97a659c

After this is merged I will create follow-up PRs updating downstream imports to pull from this plugin instead of ui/vis.

No functional changes are happening here, as nothing is even importing this code yet, so should be safe to merge assuming we are okay with the design/structure of the services.

[elasticmachine]

Pinging @elastic/kibana-app-arch

[elasticmachine]

💚 Build Succeeded

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

[elasticmachine]

💚 Build Succeeded

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

[lizozom]

LGTM

[ppisljar]

the naming got me very confused :)

we have a VisTypesService under vis_types but here we are just re-exporting types from vis_types :) and the import on top is just importing the service and setup type

[lukeelmers]

Yeah we are exporting all of the types for all services at the top level here. So for simplicity I'm just directly exporting them. However, for the setup type, we need to compose that into the VisualizationsSetup interface, and it doesn't really need to be exported by itself.

[elasticmachine]

💚 Build Succeeded

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

[lukeelmers]

@ppisljar Based on your comments I renamed VisProvider -> Vis and VisFactoryProvider -> VisFactory here. When I do a pass to update #35764 with the new imports, I can also rename any instances where they are used.

If you think it will be confusing to temporarily have something exposed as Vis even though it is consumed as a provider, we can revert back; I don't have strong feelings on this either way.