Let the user open project pairs in a new window

[louis-hildebrand]

Delivers to Project-Fungus/.github#10.
Delivers to #3.

Let users open project pairs in a new window. That would make it easier to compare multiple project pairs at once without requiring a dedicated cluster detection mechanism.

It might also be cool to hide the sidebar (project pairs list) and header (JSON file and project directory paths) so that the professor can easily screenshot only the relevant information.

Questions

• If we hide sidebar and header, what happens if the user closes the main window and leave only the ones without sidebar and header?
• Would the user want to be able to filter matches within a project pair by file? That way, if they found a match in one project and are looking for that same match in other projects, they can select only the files they want. This is probably big enough to be its own issue.