Draw.io configuration plugin.

[vyacheslavisaev]

Hi there,

What I thought it would be really nice to approach configuration from the other side. Do the extended configuration at Draw.IO. That would also allow to copy paste elements with already defined behavior (display options like: blinking, alarm sensitive, alarm color and etc ). Currently it would look like to generate the list of possible parameters and insert them into the object as XML attributes.

Work flow:

1. Create diagram at Draw.io
2. Open diagram at Grafana-flowchart.
3. Grafana-flowchart adds a template of possible parameters into the Draw.io objects.
4. Edit properties at the Draw.io.

The next step would be to develop a plugin for Draw.io. It would include a property editor window specific to Grafana-flowchart properties.

Related #224.