Perhaps technically deprecate templating of calling scripts

[jlnav]

The idea and implementation of templating calling scripts was produced before there was a from_yaml() included in libE's API. Everything that we currently template in the python calling scripts can just simply be loaded from the file, then we use jinja only on the submission scripts.

Then assuming from_yaml() is stable, we will no longer have to update the python scripts as the API changes, or if we simply want to add more templated variables.