Add the German Neo layout

[hirnsushi]

Is your feature request related to a problem? Please describe.
I've been using the German Neo layout for years with my Model 100 but it's always a pain to change keys in Chrysalis because there's no support for it in the UI.

Describe the solution you'd like
The layout is already in the source here /data/cldr/keyboards/chromeos/de-t-k0-chromeos-extended.xml but doesn't get picked up by /tools/precompile/cldr_data.js if I understand the code correctly.
I'd love for it to get added to the UI, here's what it looks like for reference https://www.unicode.org/cldr/charts/40/keyboards/layouts/de.html#de-t-k0-chromeos-extended

Describe alternatives you've considered
Currently I switch Chrysalis to the German QWERTZ layout then get a regular keyboard with Neo keycaps to check what key I need to set in Chrysalis to end up with the results I want.
Works but is very annoying to use which ultimately means I don't customize my 100 a lot, which I'd like to.

Additional context
Mostly using the 100 under Linux, if that matters.