externals: Add SDL 2.0.12

Co-authored-by: Morph <39850852+Morph1984@users.noreply.github.com>

applets: Send focus state change message on applet state change

Fixes the softlock after the controller applet exits in Mario Kart 8 Deluxe.

nvdrv: Cleanup CDMA Processor on device closure

Project Eleuthia - On-Screen Keyboard and Error Applet Overlays

Since Bintray is (soon to be) no more, there needs to be a way to
acquire SDL2. Since 20.04's version is older than our minimum required
version (2.0.12), add it as an external.

cmake: Remove use of bintray for externals.

- Bintray will be deprecated on May 1st 2021 (https://bintray.com/)
- We were previously using this for Qt (non-Windows) and SDL.
- I've moved to bundled SDL on Windows.

InputCommon: Address mapping and naming issues with SDL2

The Qt Software Keyboard frontend attempts to mimic the software keyboard rendered by the Nintendo Switch.
This frontend implements multiple keyboard types, such as the normal software keyboard, the numeric pad software keyboard and the inline software keyboard.
Keyboard and controller input is also supported in this frontend.
Keyboard input is handled as native keyboard input, and so the on-screen keyboard cannot be navigated with the keyboard arrow keys as the arrow keys are used to move the text cursor.
Controller input is translated into mouse hover movements on the onscreen keyboard or their respective button actions (B for backspace, A for entering the selected button, L/R for moving the text cursor, etc).
The text check dialogs can also be confirmed with controller input through the use of the OverlayDialog

Massive thanks to Rei for creating all the UI for the various keyboards and OverlayDialog. This would not have been possible without his excellent work.

Co-authored-by: Its-Rei <kupfel@gmail.com>

Co-authored-by: Its-Rei <kupfel@gmail.com>

An OverlayDialog is an interactive dialog that accepts controller input (while a game is running)
This dialog attempts to replicate the look and feel of the Nintendo Switch's overlay dialogs and
provide some extra features such as embedding HTML/Rich Text content in a QTextBrowser.
The OverlayDialog provides 2 modes: one to embed regular text into a QLabel and another to embed
HTML/Rich Text content into a QTextBrowser.

Co-authored-by: Its-Rei <kupfel@gmail.com>

Moves the existing meta type registration into its own function and adds registration of common integral, floating point and string types.
This function is also now called in the constructor of the GMainWindow instead of on starting a game.

We reset all the button states to 0 except the first index (which has all the buttons as pressed) to prevent a button hold being interpreted as a button that was pressed once on the first poll.

Used by Monster Hunter Generations Ultimate

Avoids unnecessary console spam when the inline software keyboard is used.

common/log: Move Log namespace into the Common namespace

Follows our predominant coding style. Also explicitly specifies the move
constructor/assignment operator as well.

Forgot to move this over when I moved the rest of the source files with
lacking namespaces over.

core: settings: Add setting for debug assertions and disable by default.

- Removes a dependency on core and input_common from common.

- This is a developer-only setting and no longer needs to be enabled by default.
- Also adds "use_auto_stub" setting to SDL frontend while we are here.
- Supersedes #1340.

k_resource_limit: Cleanup of member variables/headers

applets/controller: Hook up the "Motion" button functionality

kernel/process: Replace process resource limit instance with the kernel's resource limit

engine_interface: Add missing virtual destructor

vk_master_semaphore: Add missing const qualifier for IsFree()

vk_texture_cache: Make use of bit_cast where applicable

texure_cache/util: Resolve implicit sign conversions with std::reduce