Ability to provide custom component for <Account>

[KKings]

The <Account /> React component is added within the AppHeader.tsx but does not provide an easy way to override without overriding the entire AppHeader. It would be great to have the ability to override the <Account /> and the wrapping link through an admin override. Another nuance is that if you set the avatar to null, the Account Link still renders, just no icon to click.

Use Case
Ability to enhance the Account button to make it a Popup with links, such as "Profile", "Settings", "Logout" or other custom views.