This implements backtraces so we don't have to tell users how to use gdb anymore.

This prints a backtrace after abort or segfault is detected. It also fixes the log getting cut off with the last line containing only a bracket. This change lets us know what caused a crash not just what happened the few seconds before it.

I only know how to add support for Linux with GCC. Also this doesn't work outside of C/C++ such as in dynarmic or certain parts of graphics drivers. The good thing is that it'll try and just crash again but the stack frames are still there so the core dump will work just like before.

This simplifies the logging system.

This also fixes some lost messages on startup.

The simplification is simple. I removed unused functions and moved most things in the .h to the .cpp. I replaced the unnecessary linked list with its contents laid out as three member variables. Anything that went through the linked list now directly accesses the backends. Generic functions are replaced with those for each specific use case and there aren't many. This change increases coupling but we gain back more KISS and encapsulation.

With those changes it was easy to make it thread-safe. I just removed the mutex and turned a boolean atomic. I was planning to use this thread-safety in my next PR about stacktraces. It was actually async-signal-safety at first but I ended up using a different approach. Anyway getting rid of the linked list is important for that because have the list of backends constantly changing complicates things.

input_common: Disable sdl raw input mode

vic: Specify sws_scale height stride.

externals: Update sdl2 to 2.0.16

settings: Fix MSVC issues

According to https://stackoverflow.com/questions/469508, we run into a
MSVC bug (since VS 2005) when using diamond inheritance for
RangedSetting.

This explicitly implements those functions in RangedSetting. GetValue is
implemented as just calling the inherited version. The explicit
converson operator is reimplemented. I opted for this over ignoring the
warning with a pragma since this specifies the inherited behavior, and I
have now less faith in MSVC to pick the right one.

In addition, we mark destructors as virtual to silence what I believe is
a fair MSVC compilation error.

settings: Implement settings ranges

texture_cache: Split out template definitions

main: Avoid stopping emulation when taking a screenshot

Silences a sws_scale runtime warning about unaligned strides.

memory: Clean up code

configure_general: Swap positions of speed limit and frame limit options

vp9: Ensure the first frame is complete

yuzu-cmd/CMakeLists: Correct attribution for this function.

Silences a runtime error due to the first frame missing the frame data, and being set to hidden despite being a key-frame.

Respect Vulkan bufferImageGranularity

input_common: Improve SDL joystick and hide toggle option

Add description to fast gpu time option

common: uuid: Add hash function for UUID

nvdec: Better logging for unimplemented codecs

yuzu-cmd: hide mouse cursor when started fullscreen

settings_ui: Add emulated joystick position dot to controller preview

astc_decoder: Various performance and memory optimizations

nvdec: Fix VP9 reference frame refreshes

This was mainly used to keep track of mapped buffers for later unmapping.  Since unmap is no longer implemented, this no longer seves a valuable purpose.

With reference frames refreshes fix, we no longer need to buffer two frames in advance.
We can also remove other unused or otherwise unneeded variables.

This resolves the artifacting when decoding VP9 streams.