Add barebones react app to webview

[ibolton336]

Done:

• Move from dist -> out
• Add js and css scripts to sidebar webview html
• Add webpack config for views alongside extension webpack config
• Barebones react app added with messaging back to the vscode extension
• Added a callback for the webview event listener so that the webview exists before the listener is setup. This was breaking the extension and preventing the activation function from running without erroring
• toggle between panel and webview still works - had to set the listener in 2 places so created a utility function to hold the handler. webviewMessageHandler.ts

TODO:

• need to setup nodemon or a watcher so we dont have to compile everytime we make a change