Pipeline migrated fromAzure DevOps 🎉

This pull request introduces several new GitHub Actions workflows and updates existing ones to streamline the CI/CD process. The most significant changes include the addition of new workflows for Linux and Nix testing, the introduction of a new action for processing Pester test results, and updates to existing workflows to improve compatibility and functionality.

New Workflows and Actions:

• .github/actions/test/linux-packaging/action.yml: Added a new action for testing basic Linux packaging. This action captures the environment, downloads build artifacts, extracts files, fixes permissions, and uploads packages.
• .github/actions/test/nix/action.yml: Added a new action for testing PowerShell on non-Windows platforms. This action captures the environment, downloads build artifacts, extracts files, fixes permissions, runs tests, and uploads test results.
• .github/actions/test/process-pester-results/action.yml: Added a new action for processing Pester test results. This action converts JUnit test results to CTRF format, publishes the test report, and uploads the test results as artifacts.

Workflow Updates:

• .github/workflows/linux-ci.yml: Added a new workflow for Linux CI that includes multiple jobs for building PowerShell, running unelevated and elevated tests, and verifying xUnit test results.
• .github/workflows/windows-ci.yml: Updated the paths and branches for triggering the workflow to include all necessary files and directories.

Code Enhancements:

• tools/ci.psm1: Updated theInvoke-CITest andInvoke-LinuxTestsCore functions to support an additionalOutputFormat parameter, allowing for more flexible test result formats.[1][2][3][4][5][6][7]

These changes aim to enhance the CI/CD pipeline by adding new testing capabilities, improving test result processing, and ensuring comprehensive test coverage across different platforms.