Visdom: Support for Jupyter Notebook

[wuyujack]

Is your feature request related to a problem? Please describe.
I'm always frustrated when I am using visdom in cloud computing resources since it's difficult or not available for me to have an additional port for the visdom visualization. This largely limited my work efficiency.

Describe the solution you'd like
While there is a support for Tensorboard with Jupyter Notebook and Jupyter Lab, there is no support for visdom in jupyter notebook. If the visdom can integrate with the Jupyter Notebook or Jupyter Lab such that I can start the visdom in Jupyter Notebook or Jupyter Lab and also visualize the results in Jupyter Notebook, that should be much more convenient and largely reduce the manual work I need to do.

[JackUrb]

The Tensorboard support was created by an external collaborator - likewise we'd welcome similar contributions. At the moment this isn't on our roadmap though.

[lukacu]

Visdom works with server proxy extension for Jupyter, the only problem is that is a bit hard to configure correctly because every proxied service is prefixed with a path, you have to then configure Visdom to use this path internally as well. This is due to #411 which was meant to solve the problem of absolute paths, but it only removed the host from the URLs, they are still absolute. The underlying problem is that Tornado only supports generating such URLs. I have identified a possible solution, but it only works for static resource URLs, are there any other URLs that are generated somewhere?