docs: update README for Ares warpgate templates with new structure and details

**Changed:**

- Rebrand from "Dreadnode Warpgate Templates" to "Ares Warpgate Templates" and update all references to Ares and new repository links
- Revise overview and template descriptions to clarify agent roles and architecture (red/blue team, CLI, orchestrator, GPU, AMI)
- Update and expand template matrix tables to reflect new image types, platforms, and roles, removing old/obsolete templates and sections (Crucible, Ray, GOAD)
- Rewrite quick start, usage, and validation instructions for current Warpgate workflow, including new multi-arch, GPU, and AMI build examples
- Update directory structure and template configuration documentation for new layout and template design
- Clarify prerequisites, environment requirements (GITHUB_TOKEN, AWS creds), and runtime instructions for each major agent image
- Remove outdated sections and simplify documentation to focus on Ares agents, containers, and AMIs
- Replace links, badges, and support information to align with the current Ares and Warpgate ecosystem

Author: l50