[WSL] Prepare kinetic for common snap use cases

Users of Ubuntu WSL might be surprised by unexpected dependencies when dealing with snaps. The Ubuntu WSL development team is looking for ways to let early adopters to experiment some snapd support in Kinetic, while still providing the most seamless experience for them. Tests done in WSL instances showed surprises that we should mitigate soon.

Some examples are:

* Sublime Text and Sublime Merge apps silently depend on libgl1. This seems a bug which we didn't yet figure out how to fix in the snaps themselves. Being such hidden dependencies, we'd expect to soon find similar cases as those.

* Flutter snap provides all dependencies and runs without issues, but apps compiled by Flutter requires libgl1, libegl1 and libgtk-3-0 present in the system during development. Attempting to just run any app compiled with Flutter during development will result in crash due those libs not being found. Most likely, once package as snaps, those apps will behave as expected, if the packager lists dependencies properly. The issue reported here affects the app developer experience.

One solution for those problems is seeding for Ubuntu WSL specifically:

- libgl1
- libegl1
- libgtk-3-0

Experienced Ubuntu users would figure out how to overcome those issues very quickly, but we should expect that most of Ubuntu WSL userbase won't fit in that persona.