Enabling MCP to give responses in time-series

[Maskoff0]

The MCP initially returned gauged response but this is a considered limiting .Improving it to time-series is a considerable improvement

The MCP is a simple demo-like implementation.That is a contratin considering it will be used to metrics purposes form cloud based application.I think it should be production-ready.

### **Solution**:
**Describe the solution you'd like**  
I've added the time-series enabling implementation.

Also improved it by decoupling the hard coded prometheus url
Added a query_range support with start,end and step fields

### **Additional info**

My goal was to turn the previous prometheus query string adapater into a real MCP metrics server

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[LorenzoTettamanti]

Hi @Maskoff0 thanks for opening the issue and for your PR #223 . I'm testing your PR right now. I'll merge it this evening