poc: add a toolbar into test runner

[filiphric]

Some comments on this:

• the toolbar is now basically a separate vue app that uses the same props as the plugin
• so far it can only render and copy contents of all props into clipboard
• it works in snapshots
• it does not make too much sense. yeah, there is a copy button and potentially it could copy anything we want, but having it at the top of the toolbar does not really make sense. I could see this having a potential for some global actions, like saving list of APIs into a file or something but not sure