[Epic] implement Testing Framework for Docs Code Snippets

[interurban]

Objective:
To ensure the accuracy, reliability, and up-to-date status of code examples in the Pulumi documentation by implementing a robust testing framework that integrates with our GitHub PR workflow and includes scheduled cron jobs.

Background:
Our documentation is a critical resource for users to understand and effectively implement Pulumi solutions. Maintaining high-quality, executable code examples is essential for providing clear and accurate guidance. To achieve this, we've requre a testing framework that automatically tests code snippets both before merging PRs and on a regular schedule to catch out of date code examples and flag them for remediation..

Goals:

Pre-Merge Testing: Integrate the testing framework into the PR workflow to automatically test code snippets in the static/programs directory. This ensures that all examples are functional and correct before they are merged into the main documentation.
Scheduled Testing: Implement a cron job that regularly tests all code snippets to catch and rectify any issues that arise from changes in Pulumi’s APIs or dependencies.
Makefile Support: Allow example programs to include a Makefile with a test target, enabling more complex testing scenarios beyond the default pulumi preview.
Enhanced Shortcode Flexibility: Update Hugo shortcodes to import any arbitrary file from an example program, enhancing the documentation’s ability to showcase diverse and complex examples.
Documentation and Guidelines: Provide comprehensive documentation on how to use the testing system and contribute code examples, ensuring consistency and ease of use for all contributors.

Tasks:

• Integration of testing framework into GitHub PR workflow.
• Setup and configuration of cron job for regular testing.
• Documentation of testing procedures and shortcode usage in our public readmes
• Implementation of Makefile support for complex testing scenarios.
• Update and deploy Hugo shortcode enhancements.
• Alert doc-ops for code example test cron job failures #13931
• Enable kubernetes code testing (currently K8 tests will fail on PRs and Cron, as we have no cluster in the build process today)