v2.0 - LoupeDeck SDK v6

Add PressToTalkCommand class for PTT functionality

Introduce PressToTalkCommand class in Loupedeck.Steinerd.AudioSwitcherPlugin.Actions namespace. This class inherits from PluginDynamicCommand and implements INotifyPropertyChanged. It manages PTT functionality, allowing users to hold a button to enable communication and release it to mute. Added PTTState property to track PTT state. Implemented OnPropertyChange to handle property changes and mute/unmute the communication device. Overrode ProcessButtonEvent and ProcessTouchEvent to handle events and update PTTState. Overrode GetCommandImage to provide visual representation of PTT state.