* Make the synthetic "base name" property double underscore prefixed,
since internal, and to avoid future conflicts w/ YAML format add'ns.
* Switch to PS hash dictionaries for our metadata collections for saner
data inspection/use.
* Use unified config template repo that uses an external
build matrix YAML file.
* Proper handling for onboard keyboards, including splits, and
supports for appending the right build matrix once selected.
Peter Johanson