Implement a native templater replacement, which can be packaged with the sysadmin binary

[edbrown23]

Currently, the first "stage" of hooks is the templating step. This step uses a python script to fill out jinja2 templates that services being managed by sysadmin may require. However, this introduces a python dependency to sysadmin which is largely unnecessary/unwanted. A native templater, either in the form of an external script which can be statically linked and packaged or by integrating templating directly in the sysadmin process would avoid this dependency.