Add Model Context Protocol (MCP) API

[martin-lizner]

Read-only MCP API, vibe coded with Cursor IDE, tested by human. Experimental/PoC quality, doc will follow if accepted.

Intended use:

• External chatbot interaction
• IDE integration
• Data analysis / Troubleshooting

Dev description:

• Add mcp-api and mcp-impl modules with REST integration (rest-impl)
• Wire Spring Boot and web layer; extend endpoint mappings (gui, rest-impl)
• Add unit tests for MCP service, audit delta builder, and audit filter builder

Cursor IDE MCP definition example:
{
  "mcpServers": {
    "midpoint-local": {
      "type": "streamableHttp",
      "url": "http://localhost:8080/midpoint/ws/mcp",
      "headers": {
        "Authorization": "Basic xxxxxxx"
      }
    }
  }
}

prompt examples:

• midpoint-local, explain user administrator
• midpoint-local, Mr. Smith was requested a role recently, give me phone number of person who is holding the approval
• midpoint-local, fetch CN attributes on my LDAP resource
• midpoint-local, what happened to user martin today? he cannot login