feat: Add Random Condition

[jshlbrd]

Description

• Adds a Random choice condition
• Adds a patterns.libsonnet file
• Removes raw metadata support from the Copy processor

Motivation and Context

We have some use cases where we need to integration test new configurations and deployments with high-volume datasets, but we don't want to fully process the entire dataset (which would cause a 2x increase in cost during the test), so this PR adds a "random choice" condition that can be used to selectively process data.

The intended use of this for integration testing is to pair it with the Drop processor, which would cause the application to randomly drop events from a workflow. To support that, I added the patterns.libsonnet file (this mimics other files we've used internally) -- this file contains pre-configured and commonly used data processing patterns that can be applied across many pipelines. As a bonus, I added a pattern for calculating SHA256 hashes for both plaintext and binary data.

This also includes an update to the Copy processor and jsonnetfmt'ing of the libsonnet files.

How Has This Been Tested?

Tested locally using the file app.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[julieagnessparks]

LGTM