Add better options visualizer

**This PR adds a realtime-updating jetzt sample to the Options Page.**

A static version (demoing the text "Sa **m** ple") shows the UI of the
Jetzt view with a realtime-updating font display and colorization.

Still needs to have dark-theme support, but I wanted to get this up there
in case this was not the best way of writing this (still very new to Angular,
but I'm really digging it).

Contributions obviously welcome (and probably needed, to some extent)!