Active Tab highlight should match Windows 10 accent colour

dftf-wip 

So first there are some built in themes for Edge

Activated using this flag:

edge://flags/#edge-color-theme-picker

(available on insider channels for now)

then there are Edge exclusive themes on the store that each have their own set of rules and customizations:

https://microsoftedge.microsoft.com/addons/microsoft-edge-themes

Also,

Windows 10's accent color applies to the Edge window and tab strips, making the active tab obvious and clear in both dark/light themes.

Windows 10 personalization settings:

This is the only way it makes sense. why? because accent color is correctly applying to the whole Window of any program, including Edge's Window, which means, all tabs that are in the tab strip are part of that Window.

so active tab can't be the only element in Edge to have accent color.

this example makes it more obvious

 as you can see, the majority of the Edge's window and tab strip is blue, which is the accent color of Windows 10, which applies to all Windows of programs.

so the active tab should be identified with another color, in this case, it is the light/dark theme of the browser/Windows.

if it was the opposite way, it would be extremely inconsistent. because then every program would have the correct accent color applied to it except for Edge.