Was getting an unhandled `invalid_argument` [exception](https://en.cppreference.com/w/cpp/thread/thread/join) during
shutdown on my linux machine. This removes the need for a `StopBackendThread` function entirely since `jthread`
[automatically handles both checking if the thread is joinable and stopping the token before attempting to join](https://en.cppreference.com/w/cpp/thread/jthread/~jthread) in the case that `StartBackendThread` was never called.
Addresses https://github.com/yuzu-emu/yuzu/issues/7881 to fix linux
builds.
`YUZU_NON_COPYABLE` deletes the `T(const T&)` constructor which will
cause the implicitly defined default ctor/dtor to no-longer generate.
I have `134850146304` bytes of ram and Yuzu was saying that I had `125.59 GB`
of ram. But `125.59` is actually the amount of gi**bi**bytes I have. In
gi**ga**bytes I would have `134.9`.
Additionally, I changed the `1024 / 1024 / 1024` here into the `_GiB`
user-literals that I added a while ago(#6519).
https://www.wolframalpha.com/input/?i=134850146304+bytes
Removes common_sizes.h in favor of having `_KiB`, `_MiB`, `_GiB`, etc
user-literals within literals.h.
To keep the global namespace clean, users will have to use:
```
using namespace Common::Literals;
```
to access these literals.
Wunkolo