Previously, the template job HCL file was hardcoded using go:embed
in the binary. However, this did not allow users running Poseidon
to change its content. Now, users can change the content of the
template job HCL file using the configuration option.
We previously didn't really had any structure in our project apart
from creating a new folder for each package in our project root.
Now that we have accumulated some packages, we use the well-known
Golang project layout in order to clearly communicate our intent
with packages. See https://github.com/golang-standards/project-layout
