merge vgrid

[sameh-farouk]

please merge first #191 and #186

Changes:

• Merge vgrid into 3bot repository to /3bot/vgrid
• Update VGrid to make it works with new vlnag version
• Update filters to use latest gridproxy params
• Add new function to query node stats and add relvant models
• Update docs
• Fix examples

Related Issue:

• https://github.com/threefoldtech/3bot/issues/179