[AltServer] Moves core ConnectionManager logic to AltKit

Refactors ConnectionManager to use arbitrary RequestHandlers and ConnectionHandlers. This allows the core AltServer request logic to be shared across different targets with different connection types.

AltServer/Connections/ALTWiredConnection.h

@@ -8,10 +8,14 @@
 
 #import <AltSign/AltSign.h>
 
+#import "AltKit.h"
+
 NS_ASSUME_NONNULL_BEGIN
 
 NS_SWIFT_NAME(WiredConnection)
-@interface ALTWiredConnection : NSObject
+@interface ALTWiredConnection : NSObject <ALTConnection>
+
+@property (nonatomic, readonly, getter=isConnected) BOOL connected;
 
 @property (nonatomic, copy, readonly) ALTDevice *device;