Updated existing pre-commit hooks and added some new hooks:
- Remove trailing whitespace
- Ensure every non-empty file ends with a new line
- Check YAML file validity
- Prevent adding large files
- Ensure any scripts with shebangs are executable
Added a GitHub action to run pre-commit on every commit. Removed any
existing actions which duplicate pre-commit.
Ran pre-commit on the codebase.
* 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.
