Use vscode-messenger library for communcation between views and extension

[bhufmann]

Use vscode-messenger RPC messaging library for the VS Code extension platform [1]. This will help providing a clean way to send messages within the vscode-trace-extension components, like the extension and webviews.

Note: Don't forget to account for BigInt variables within messages, that won't be able to be sent directly with this library.

[1] https://github.com/TypeFox/vscode-messenger

[dhuebner]

@bhufmann
Very handy is also the Messenger Developer Tool to visualize the communication between the vscode-messenger components.
It is available as VS Code extension in marketplace.