[NavBar] Support stretched tabs

[jeremyputeaux]

Bug, feature request, or proposal:

Feature request

What is the expected behavior?

As seen in https://material.io/guidelines/components/tabs.html, tabs should use 100% of horizontal space when they fit and they use label space with arrows when they don't fit.
There used to be a md-stretch-tabs that seems to do this but not anymore as seen in #5286

What is the current behavior?

Currently, tabs are inline but we can't tell the tabs to use all space.

What are the steps to reproduce?

https://stackblitz.com/edit/mat-tab-nav-bar-not-using-all-horizontal-space

What is the use-case or motivation for changing an existing behavior?

Respecting the guideline. Making an easy way to do it

[mhosman]

Arrows not present?

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