[rcore] implemented saving for INPUT_GAMEPAD_CONNECT and INPUT_GAMEPAD_DISCONNECT

[ssszcmawo]

Here is the implementation for saving gamepad connection and disconnection events. I added a helper variable, prevReady, to the Gamepad structure to keep track of its previous ready state. Now it is initialized along with ready in the PlayAutomationEvent function during INPUT_GAMEPAD_CONNECT. prevReady doesn't need to be set to false or true in INPUT_GAMEPAD_DISCONNECT because when disconnection happens it will be automatically updated at the end of the loop (line 4167)