Define the 3 areas the Top Bar will provide

Problem/Motivation

Currently the Top Bar renders the the local tasks. But there is no logic, order or even an standardized way to add elements to it.

Proposed resolution

Provide 3 delimited regions where UI elements will be hooked and rendered.
Refactor how the existing local tasks are rendered so they used the standardized system created in this issue.

Remaining tasks

User interface changes

None

Introduced terminology

API changes

Data model changes

Release notes snippet