Timer: Adding rough scaffolding for new countdown Timer

Lo,

This will be a countdown timer (i.e. the inverse of the stopwatch spice); but I've currently got a couple of problems:

* I can't get the actual spice to work in duckpan server, it's copy-and-pasted from stopwatch so I presume it has the same problem as https://github.com/duckduckgo/zeroclickinfo-spice/issues/914
* It has no actual styling at all, I could do with some ideas, but I need to be able to test it first!
* it's incredibly rough'n'ready!

All help valued!