Add wgpu::Adapter API to users

[tseli0s]

"Closes" #339

There's also the alternative of strictly exposing only wgpu::AdapterInfo. Which may be desired if we don't want to give any access to the adapter itself for whatever reason (Keep in mind with the commits as they are currently we give at most a mutable ref to the adapter, which may allow someone to modify things they shouldn't). I avoided this because why hide a simple adapter when the crate exposes other parts of wgpu? And at worst, let users decide if they want to get access to the adapter.

If the function names aren't good (eg. wgpu shouldn't be there) or we need to wrap around wgpu::Adapter then lmk, I'll fix it.
Verified to work under GNU/Linux as expected.

[parasyte]

Hi @AndroGR, thanks for the PR.

I was hesitant on this one following the conversation in #339 (reply in thread) but I think what you have here is the right thing to do for now. I have just one change to request, and that's removing the mut variant of the method. I believe it is not needed.

I would also rename the method to adapter or get_adapter. (My current preference is adapter, and I am planning to rename get_frame to frame, et al. in another PR for consistency.)

[tseli0s]

I would also rename the method to adapter or get_adapter. (My current preference is adapter, and I am planning to rename get_frame to frame, et al. in another PR for consistency.)

Well, I am going to name it adapter and I'll leave it up to you to decide for the style you prefer. Although since we are returning only a reference to it I imagine adapter makes more sense here (Like some popular crates do it)

[parasyte]

Thank you!