This isn't used anywhere and not really a generic utility, so we can get
rid of it.
This also lets us remove MathUtil.cpp, since this was the only thing
within that file.
RetroAchievements Rich Presence is a script that is run periodically on a game's memory to provide a detailed text description of what the player is doing. Existing Discord presence on Dolphin would update a player's Discord status to say not just that they are using Dolphin but that they are playing, for example, Sonic Adventure 2 Battle; Rich Presence would detail that the player is in City Escape with 5 lives and 142 rings.
Activating this in the runtime simply entails loading that text script, as returned by the FetchGameData API call, into the runtime, here only determined by whether rich presence is enabled in the achievement settings. Deactivating this is done via the same rcheevos method by setting the rich presence to an empty string.
This activates or deactivates leaderboards in the rcheevos runtime similarly to achievements. The logic is much more straightforward - all leaderboards are active together; there is nothing requiring some leaderboards to be active while others are unactive, and even a leaderboard that has been submitted to in this session is still active to be submitted to again. The only criteria are that leaderboards must be enabled in the settings, and hardcore mode must be on, the latter of which is false until a future PR.
LoadUnlockData and ActivateDeactivateAchievements are the public API components responding to the FetchUnlocks and A/DAchievement (singular) private methods.
LoadUnlockData is asynchronous and performs both a hardcore and a softcore unlock call, updating the unlock map and the active status of any achievements returned from these calls.
ActivateDeactivateAchievements calls ActivateDeactivateAchievement on every achievement ID found in m_game_data, initializing the unlock map for each ID if not already found.
Both of these are currently called in LoadGameByFilenameAsync once the game has been loaded properly. There's a lock around this, to ensure that the unlock map is initialized properly by ActivateDeactivate Achievements before FetchUnlockData makes modifications to it without stalling the async portions of FetchUnlockData.
FetchUnlockData is an API call to RetroAchievements that downloads a list of achievement IDs for a game that the user has already unlocked and published to the site. It accepts a parameter for whether or not hardcore or softcore achievements are being requested, so that must be provided as well. Once it has the requested list on hand, it updates each achievement's status in the unlock map and will activate or deactivate achievements as necessary.
ActivateDeactivateAchievement is passed an Achievement ID as returned from the FetchGameData API call and determines whether to activate it, deactivate it, or leave it where it is based on its current known state and what settings are enabled.
Activating or deactivating an achievement entails calling a method provided by rcheevos that performs this on the rcheevos runtime. Activating an achievement loads its memory signature into the runtime; now the runtime will process the achievement each time the rc_runtime_do_frame function is called (this will be in a future PR) to determine when the achievement's requirements are met. Deactivating an achievement unloads it from the runtime.
The specific logic to determine whether an achievement is active operates over many fields but is documented in detail inside the function. There are multiple settings flags for which achievements are enabled (one flag for all achievements, an "unofficial" flag for enabling achievements marked as unofficial i.e. those that have logic on the site but have not yet been officially approved, and an "encore" flag that enables achievements the player has already unlocked) and this function also evaluates whether the achievement has been unlocked in hardcore mode or softcore mode (though currently every reference to the current hardcore mode state is hardcoded as false).
Update the rcheevos submodule to the most recent origin/develop, which contains a fix to the gamecube hash algorithm to politely exit if it is unable to open a file.
LoadGameByFilenameAsync sets up a volume reader and hashes the volume, then uses that hash to make the three consecutive API requests to resolve hash, start session and load game data.
CloseGame resets the m_is_game_loaded flag, wipes the queue, and destroys all the game data responses.
FetchGameData is the big one - this retrieves the logic for all the achievements, leaderboards, and rich presence, and all the relevant metadata for the game.
Added a call to the RetroAchievements Start Session API to AchievementManager. This is primarily for client-side activation, so it doesn't return much of value, aside from its success/error information, but I'm storing the return structure in case this changes in the future.
Added the ResolveHash method to AchievementManager. This is a blocking function to send a hash string to the RetroAchievements server to verify it and get a game ID back.
This was previously copying each pair out of the vector returned by
GetInterfaceListInternal() when we just need to emplace the first entry
of each pair.
