Resolves the C4146 compiler warning on MSVC.

hotkeys: Trigger actions on a separate thread

CMakeLists: Revert ad55faaa

general: Convert source file copyright comments over to SPDX

This formats all copyright comments according to SPDX formatting guidelines.
Additionally, this resolves the remaining GPLv2 only licensed files by relicensing them to GPLv2.0-or-later.

The premise behind ad55faaa was due to an issue between Conan's
libiconv package and compiling SDL2 from our externals. Since none of
our Conan externals require libiconv any longer, though, we can remove
downloading our own Boost package and just rely on Conan again.

Additionally, removing CONFIG from the find_package(boost) call fixes
issues with finding Boost on Fedora and MSYS2, which was the main
motivation for this.

Also, remove QUIET since if something goes wrong finding Boost, this
makes it harder to tell what went wrong.

loader: log the type of mismatching file-extension

input_common: Map sticks correctly when mapped sideways

service: hid: Improve accuracy of sixaxis functions

bootmanager: Don't create another screenshot request if previous one is not done yet

core/arm: separate backtrace collection

input_common: Ignore boost uninitialized local variable

ui: translate hat directions

dynarmic: Always use mmap for allocation on Linux

QObject ends up being its own translation context. But this works in our
favor. GetButtonName and GetDirectionName will share one translation the
directions such as "Left" "Right" and the ConfigureInputPlayer context
will contain translations that show up in the form, in places that aren't
those buttons.

yuzu: mention GPLv3.0 in about dialog

Follow-up to 284934eb

Fixes #8218

Clarify the Skyline Emulator license exception

`GPL-3.0-or-later OR MPL-2.0` is an SPDX expression: https://spdx.github.io/spdx-spec/SPDX-license-expressions/

Fixes #8219

ui: Fix Game Compatibility list translations

Reported by GillianMC on Discord. Looks to be a small quirk in the QT API.

setText(QObject::tr(status.text));
bringing up QObject breaks the link with the GameListItemCompat

hidbus: Implement hidbus and ringcon

dynarmic: Fix race when switching page tables

Fixes for Mario 64

hle: kernel: Use std::mutex instead of spin locks for most kernel locking.

ui: Set Link Color when setting theme

emu_window_sdl2: Set window size to display dimensions for exclusive fullscreen