Switch Windows to containers running in WSL

[danielmarbach]

This pull request significantly refactors the action to remove all dependencies on Azure Container Instances for Windows runners. Instead, it now runs PostgreSQL inside a WSL2-based Docker container on Windows runners, aligning the approach with Linux runners and simplifying the setup and cleanup processes. The documentation and input parameters have been updated to reflect these architectural changes.

Major architectural changes:

• Replaced the use of Azure Container Instances on Windows runners with WSL2-based Docker containers. The scripts now install and manage Docker inside a WSL2 distribution, launch the PostgreSQL container there, and ensure the WSL instance remains alive for the duration of the job. (Ffa4187eL15R15, cleanup.ps1L15-R17)
• Removed all Azure login and resource group management steps from the workflow, scripts, and documentation. [1] [2] [3] [4]

Input and interface changes:

• Removed the tag input parameter from the action (action.yml, index.js, setup.ps1, and related workflow/example usages). The action interface is now simpler, and the documentation has been updated to indicate that only the connection string name is required. [1] [2] [3] [4] [5] [6] [7]

Documentation and usage updates:

• Updated the README.md to clarify that on Windows runners, PostgreSQL runs inside WSL2 and no Azure resources are needed. Simplified setup and cleanup instructions, and removed references to Azure-specific environment variables and steps. [1] [2] [3] [4]

Script and reliability improvements:

• Added logic to automatically install and configure WSL2 distributions, constrain VM resources, and keep the WSL instance alive using a D-Bus session. Improved error handling and output for these steps. (Ffa4187eL15R15)
• Changed the PostgreSQL connectivity check to use a version-agnostic SELECT 1 query instead of --list, improving compatibility with different server/client versions.

These changes make the action easier to use, more consistent across operating systems, and remove the requirement for Azure access on Windows runners.