Add default builtin import paths for newly created files

When creating new files (device or otherwise) they are not yet present in the compile commands, meaning they will have no known include paths (other than relative paths). Untill a configuration is done the user will thus encounter various 'no template found' messages and similar.

To can make this a little nicer by trying to find the currently used core library import paths from other, configured, devices and provide these implicitly to newly created files.