Add more repositories and sync shared templates

[mmstick]

Tested locally. All but cosmic-initial-setup was able to update and build at the moment. This will add some files that should be kept in sync across projects in a templates directory.

A shared cargo.just module can be imported into a project's justfile with mod cargo 'cargo.just'. Recipes from it can be called with vendor: cargo::vendor, run *args: (cargo::run args), and just cargo vendor-extract. We can use this to ensure our build and vendoring recipes are using the correct arguments.

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[jackpot51]

I think pop-launcher does not have to be versioned alongside the other repos

[jackpot51]

Are you sure this script works on all of these repos, especially cosmic-settings?

[mmstick]

I can push a test PR for cosmic-settings with the commit it made.