Move balenaDash to version 2 of the browser block

[phil-d-wilson]

Version 2 of the browser block is now available, which includes an API for dynamic configuration:
https://github.com/balenablocks/browser

This project should be updated to use the new block. The Tahora method of changing the URL can now be replaced by using the API directly. An example of a project which does this is here:
https://github.com/balena-io-playground/browsercontrol

This could be used as the Tahora replacement, or serve purely as a guide for how to use the browser block API.