renderer_vulkan/wrapper: Add a Vulkan wrapper (part 1 of 2)

gl_rasterizer: Synchronize stencil testing on clears

services: time: Implement CalculateSpanBetween.

audio_core: Accept Audren REV8

am: Implement VR related APIs

services: hid: Stub InitializeSevenSixAxisSensor.

Port citra-emu/citra#5089: "Set render window's focus policy to Qt::StrongFocus"

Port citra-emu/citra#4906: "citra_qt: fix the stuck in fullscreen mode"

Port citra-emu/citra#5093: "Replace non-commercial icons"

Co-Authored-By: Valentin Vanelslande <vvanelslandedev@gmail.com>

engines/const_buffer_engine_interface: Store image format and types

- Used by Super Smash Bros. Ultimate v7.0.0.

- Used by Super Smash Bros. Ultimate.

Implement (and stub) VR related APIs in AM sysmodule.

This fixes issue #2938

The intention behind a Vulkan wrapper is to drop Vulkan-Hpp.

The issues with Vulkan-Hpp are:
- Regular breaks of the API.
- Copy constructors that do the same as the aggregates (fixed recently)
- External dynamic dispatch that is hard to remove
- Alias KHR handles with non-KHR handles making it impossible to use
smart handles on Vulkan 1.0 instances with extensions that were included
on Vulkan 1.1.
- Dynamic dispatchers silently change size depending on preprocessor
definitions. Different files will have different dispatch definitions,
generating all kinds of hard to debug memory issues.

In other words, Vulkan-Hpp is not "production ready" for our needs and
this wrapper aims to replace it without losing RAII and exception
safety.

This information is required to properly implement SULD.B. It might also
be handy for all image operations, since it would allow us to implement
them on devices that require the image format to be specified (on
desktop, this would be AMD on OpenGL and Intel on OpenGL and Vulkan).

maxwell_to_vk: implement signedscaled vertex formats

yuzu: Remove exit lock for game pausing

Minor Readme Changes

Use the correct directory for Qt Plugins

xmad: fix clang build error

gl_shader_decompiler: Implement legacy varyings

Added Discord shield and direct link to contribution guide

Port citra-emu/citra#5106: "gdbstub: Ensure gdbstub doesn't drop packets crucial to initialization"