Consolidate Ansible Galaxy requirements

[QiMata]

Summary

• merge role and collection dependencies into a single root requirements.yml and raise the community.general minimum to 8.6.0
• update documentation to reference the unified dependency file and align version guidance
• remove the redundant src/requirements.yml file that is now folded into the root requirements list

Testing

• yamllint requirements.yml
• ansible-galaxy install -r requirements.yml (fails: 403 Forbidden when contacting galaxy.ansible.com)

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https://chatgpt.com/codex/tasks/task_e_68dc35db9130832a911de3a5f99cc663