[terra-application-v3] Enhance "active" state APIs for components that feature portaling

[tbiethman]

Story

Description

As a consumer, I would like to know when my component is present on the DOM ("active")

Motivation

So that I can accurate query the DOM for components that I render.

Definition of Done

We'll know we're done when we expose an API from portal-ed framework components that will tell consumers when they have reached the DOM.

Details

I have created a rough implementation of what I'd expect: terra-application-v2...application-v2-active-state-changes

Existing components that need (passive) changes:

• Workspace
• PrimaryNavigationLayout
• Page

New components in V2V3 scope that will require similar implementations:

• Modal