Update libraries to call `init` and specifiy dependency versions

[sonnyp]

See #736 (comment)

Let's discuss what's best first

[sonnyp]

One thing worth mentioning is that demos should sort of survive a sdk/platform bump because users can save them on their disk.

Maybe we specify all dependency versions in imports?

[theCapypara]

Some thoughts of mine:
#732 (comment)

[...] it's only required for libraries that have more than one version (Gtk, GtkSource, etc.) and it's recommended for Adw.

It's also not needed for direct dependencies of Gtk, such as Gdk.
You can take Workbench itself as a reference for what needs versions: https://github.com/sonnyp/Workbench/blob/main/src/init.js#L1-L7

An additional thing:
We should find out if Pango 1 is an implicit dependency of GTK, otherwise the release of Pango 2 could break things and we should also add Pango to the list.

[theCapypara]

workbenchdev/demos#25 would also help here with identifying breaking changes when Sdk version is bumped. workbenchdev/demos#24 even more so.

[UrtsiSantsi]

I think pango 1 is dependency for gtk 4 and pango 2 is gtk 5 material, but I'm not 100% sure.

[sonnyp]

Related #879