Add SUPPORT.md

[udid-aws]

Description

Adds a SUPPORT.md to the repo root describing how users get help, and links it from the README.

Structure adapted from the agent-toolkit-for-aws SUPPORT.md, tailored to this repo:

• Documentation — points to this repo's docs site (home, Getting Started, and the Skills / Custom Agents / MCP Servers catalogs) plus the DevOps Agent User Guide.
• Bug reports — links to the bug-report.yml issue template.
• New tool requests — links to the community-request.yml issue template, and cross-links CONTRIBUTING.md for self-contributors.
• Security vulnerabilities — directs to the AWS vulnerability reporting page (no local SECURITY.md exists in this repo).
• AWS support — Support Center and re:Post for AWS service issues.

Also adds a Support section to the README linking to SUPPORT.md.

Testing

• Verified the docs catalog links resolve to real pages (Skills, Custom Agents, MCP Servers all exist in the mkdocs nav).
• Confirmed the issue-template ?template= filenames match the templates in .github/ISSUE_TEMPLATE/.