FEATURE SUGGESTION: Add blockchain status icon to blockchain element in Visual Studio Code N3 plugin

[roschler]

I would like to see a status icon next to the NEO Express in the N3 plugin display area. Something that at least would show you if the blockchain is started or not. Perhaps a light GREEN LED if it's started, a dim RED one if it's not, etc. I know that the QUICK START window pane will show you the Start NEO Express button if the blockchain is not started, but sometimes I forget to look at that when I'm doing batch commands from a Terminal window and then I miss up my current environment. If I could glance at the blockchain element in the BLOCKCHAIN window pane, that wouldn't happen.

[devhawk]

this belongs in the N3 tracker repo