v0.1.0-kubeflow-v1.0

Feature/notebook image (#4)

* Makes notebook image configurable

Uses kfdef parameters to inform the image to platiagro/notebook.
This will allow custom configurations for GPU.

* Adds a custom configuration file for GPU environments

Sets platiagro/platiagro-notebook-image-gpu:0.1.0 as default docker image
for kfdef/kfctl_platiagro_tls_gpu.v0.1.0.yaml.

* Adds all platiagro/pipelines env variables to manifest

Makes env variables explicit in manifests so it's easier to change
values.