Add Prometheus MCP Server to registry (github#163)

* Add Prometheus MCP Server to registry

This commit adds the Prometheus MCP Server to the official Docker MCP Registry.

The server provides:
- PromQL query execution against Prometheus
- Metrics discovery and exploration
- Authentication support (basic auth and bearer token)
- Multi-tenant support for setups like Cortex, Mimir, or Thanos

* Update prometheus server config

Author: pab1it0

servers/prometheus/server.yaml

@@ -0,0 +1,34 @@
+name: prometheus
+image: ghcr.io/pab1it0/prometheus-mcp-server
+type: server
+meta:
+  category: monitoring
+  tags:
+    - ai
+    - devops
+    - llm
+    - model-context-protocol
+    - prometheus
+    - metrics
+    - monitoring
+    - observability
+about:
+  title: Prometheus
+  description: A Model Context Protocol (MCP) server that enables AI assistants to query and analyze Prometheus metrics through standardized interfaces. Connect to your Prometheus instance to retrieve metrics, perform queries, and gain insights into your system's performance and health.
+  icon: https://upload.wikimedia.org/wikipedia/commons/3/38/Prometheus_software_logo.svg
+source:
+  project: https://github.com/pab1it0/prometheus-mcp-server
+config:
+  description: Configure the connection to your Prometheus server
+  env:
+    - name: PROMETHEUS_URL
+      example: http://host.docker.internal:9090
+      value: '{{prometheus.prometheus_url}}'
+  parameters:
+    type: object
+    properties:
+      prometheus_url:
+        type: string
+        description: The URL of your Prometheus server
+    required:
+      - prometheus_url