Add default Zephyr template for single-core targets

Type: Feature Request

Add to `...\.vscode\extensions\arm.cmsis-csolution\templates` a generic Zephyr template.

This could be similar to https://github.com/VladimirUmek/alif_ensemble-cmsis-dfp/tree/dev/Alif_CMSIS/Template/Zephyr

Documentation Link should be https://mdk-packs.github.io/vscode-cmsis-solution-docs/zephyr.html
