Removes the old GUI1 code base and reduces the Rust code footprint by removing unused code.
# Important Notes
Updates build scripts and reformats part of the codebase with the autoformatter.
This PR adds support for the new Vue-based GUI (aka `gui2`).
The user-facing changes are primarily:
* support for `./run gui2` and `./run ide2` commands (that build just the new GUI and the whole IDE package with new GUI embedded — respectively);
* the top-level `test` and `lint` commands will now invoke the relevant commands on the new GUI
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Co-authored-by: Paweł Grabarz <frizi09@gmail.com>
