Add pipelines code

[piotrpdev]

Description

Adds OpenShift Pipelines code to download a model from S3, build an image that uses that model, does some basic testing on the image, and uploads the image to Quay.

Also adds some documentation on how to use/deploy the pipeline code.

Resolves #2, resolves #4, resolves #1

How Has This Been Tested?

See azureml-model-to-edge project on local-cluster, this is where I have tested and made sure all of this code works.

Merge criteria:

• The commits are squashed in a cohesive manner and have meaningful messages.
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has manually tested the changes and verified that the changes work

[israel-hdez]

I quickly read the code. I didn't inspect in detail.

I'm approving because I think this is way more than enough for the PoC.

[grdryn]

I've left some comments, suggestions, and questions inline, but it's looking good generally 👍

I wonder if some of the stuff in the pipelines dir here should be either put into the acm/odh-core/ directory, or maybe alternatively a new application should be added to acm/registration/ repo, to get ACM to synchronize the cluster with what's defined here?