Local Mock Runtime

[4meta5]

This would be useful for testing the macros in this repo. It would also ensure that the CI reflects their usability rather than compilation which often passes for macros without necessarily passing in their invocation.

It would also help break the dependency upgrade process into smaller chunks as well wherein updating the macros to work for this mock runtime would act as an intermediate step before updating the templates. This intermediate step would be helpful during complex dependency upgrades.