docs: add Proxmox setup guide for Terraform (#2)
## Summary
Add Proxmox setup documentation for Terraform with dedicated role and minimal privileges.
## Changes
- Add `docs/proxmox-setup.md` with complete setup guide
- Dedicated `TerraformRole` (no Administrator role needed)
- Both Web UI and CLI procedures
- SSH configuration for bpg/proxmox provider
## Privileges (Proxmox 9.1)
| Category | Privileges |
|-----------|------------|
| Datastore | `Allocate`, `AllocateSpace`, `AllocateTemplate`, `Audit` |
| System | `Audit`, `Console`, `Modify` |
| VM | `Allocate`, `Audit`, `Clone`, `Config.*`, `Console`, `Migrate`, `PowerMgmt`, `Snapshot`, `Snapshot.Rollback`, `GuestAgent.Audit`, `GuestAgent.FileRead` |
| Pool | `Allocate`, `Audit` |
| SDN | `Use` |
> ⚠️ `VM.Monitor` deprecated in Proxmox 9 — use `VM.GuestAgent.Audit` and `VM.GuestAgent.FileRead` instead.
## Related
Closes #1
Co-authored-by: darnodo <sepales.pret0h@icloud.com>
Reviewed-on: #2
Damien Arnodo
90232da467