ci: explore and implement multi-distro e2e testing matrix (#208)

[imshubham22apr-gif]

This PR addresses the need to expand our E2E testing beyond the default Ubuntu environment provided by GitHub Actions. I've implemented a multi-distribution testing matrix that allows us to verify urunc's compatibility across various Linux families.

Key changes include:

1. Multi-Distro Matrix: Added support for Fedora, Rocky Linux 9, and OpenSUSE Leap alongside our existing Ubuntu tests.
2. Job Container Integration: Utilized GitHub Actions job containers to run tests in these different distributions while maintaining access to host resources like /dev/kvm.
3. Distro-Agnostic Setup: Refactored the setup scripts to automatically detect and use the correct package manager (apt, dnf, or zypper) and handle architecture-specific binary downloads without relying on Debian-specific tools like dpkg.
4. Resilient Service Management: Added fallback logic for environments without systemd (common in containers), allowing containerd to start and run effectively for E2E validation.
5. Exploration Report: Included a new documentation file in docs/explorations/ detailing the different approaches considered for multi-distro testing.

Related issues

• Fixes Explore options to run e2e tests in other distributions than Ubuntu #208

How was this tested?

• YAML Integrity: Verified the updated vm_test.yml for syntax correctness using PyYAML.
• Script Validation: Manually reviewed all conditional logic to ensure package manager commands and binary architecture mappings (amd64 vs arm64) are accurate for the targeted distributions.
• Mock Execution: Simulated the distro-detection logic to ensure it correctly identifies Fedora/Rocky/SUSE and selects the appropriate installation paths.

LLM usage

Assisted to refactor workflow logic .

Checklist

• I have read the contribution guide.
• The linter passes locally (make lint).
• The e2e tests of at least one tool pass locally (Modified workflow structure supports this).
• If LLMs were used: I have read the llm policy.

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