Add link to rrdtool script

[dani-sanchez-dorado]

Hello!

In the documentation page "https://ravada.readthedocs.io/en/latest/docs/report_rrdgraph.html" you say : "Here is a script to pass data to mi graph system (RRDgraph based). Feel free to use, distribute or modify" ... but, there is no link to anything.

I think thereis a missing link to an script to integrate rrdtool.

Thanks!

[dani-sanchez-dorado]

Ohh, so, there is no support for rrgraph? Ok