Consolidate `data/webui` configuration

The data/webui directory currently contains a separate config YAML file for each board. There are dozens of these files, even though most of their contents are identical.

This should be consolidated so that there is one base/template configuration per bus, with only small board-specific additions or overrides where necessary.

Benefits:

• Reduce the number of nearly-identical files.
• Changes to the common configuration only need to be made in one place.
• Make it easier for new boards to inherit the standard configuration.
• Reduce the chance of configurations getting out of sync.

There should only need to be a small handful of config files rather than one for every board. A small amount of scripting may be needed to generate or assemble the final configurations.