Option to use dynamic colors

[Livinglist]

Can you provide more details? The app currently offers the ability to change the theme color.

[bblacher]

I think the author would like the app to support Android Material You Dynamic color
ref: https://source.android.com/docs/core/display/material#dynamic-color

[eames-palmer]

I have a functional draft started in #794 with testing steps documented.

Unfortunately, I do not have an iOS device to confirm that the Platform.isAndroid behavior functions as expected.

Please let me know if you have any preferences on the UI wording/placement. I used "wallpaper colors." to follow a similar style to the existing preferences.

At the moment, toggling the HackerNews theme is still possible while Dynamic Colors is toggled and overrides it. I'll look into disabling that to make them mutually exclusive unless that behavior is preferred. It seems like "true black" can still be toggled when HackerNews theme is, so this may be somewhat of an existing behavior.

I will publish this after polishing that behavior.