Path / input handler (sage pipe tool)

[JBarmentlo]

Some kind of wrapper to avoid 2 errors:

• Oh shit I'm using a relative path to smth that's not being copied to Docker. (not in src)
• access inputs from sagemaker pipelines

We could overload pathlib Path.

SagemakerPath(a relative path):
# Should give a warning if 1. Path is not Relative or 2. path is not in src

SagemakerInput(input_name)
# this means if we change the way inoputs are handled we dont break all repos
# we can have nicer warnings if it doesnt exist

SagemakerOutput(outputName)
# Same as above