Add Neo4j Community Edition Azure Marketplace template

[retroryan]

Summary

• Adds a new marketplace/neo4j-ce/ Bicep template that deploys Neo4j Community Edition as a standalone VM (not VMSS), with a
  standalone managed disk that persists independently of the VM lifecycle
• Uses cloud-init (scripts/neo4j-ce/cloud-init/standalone.yaml) for provisioning instead of CustomScript extension — installs Neo4j from yum, configures APOC, mounts NVMe data disk, and runs a health check loop
• Targets the Eds_v6 VM series (NVMe-only) with pickZones() auto-detection for availability zone support and
  PremiumV2_LRS/Premium_LRS disk fallback
• Adds a dedicated CI workflow (.github/workflows/community.yml) and a standalone test suite (test_suite/test_ce/) that validates connectivity, APOC availability, Community Edition license, CRUD operations, and data persistence across VM restarts
• Extends the deployments/ framework with an Edition enum, Community Edition scenario support, and check_community_edition() validation

Key architectural decisions

• Standalone VM over VMSS — CE is single-node only; a plain VM avoids VMSS overhead (capacity management, upgrade policies) while retaining Azure service healing
• Standalone managed disk — deleteOption: Detach ensures the data disk survives VM deletion, enabling disaster recovery by reattaching to a new VM; cloud-init overwrite: false makes remounts idempotent
• No managed identity — the Enterprise template's UserAssigned identity was unused; CE removes it to eliminate a billable resource
• pickZones() auto-detection — server-side ARM function replaces hardcoded region lists, driving zone pinning for disk, public IP, and VM from a single boolean