Move text message handling into the new plugin system

src/mesh/MeshPlugin.h

@@ -0,0 +1,49 @@
+#pragma once
+
+#include "mesh/MeshTypes.h"
+#include <vector>
+/** A baseclass for any mesh "plugin".
+ *
+ * A plugin allows you to add new features to meshtastic device code, without needing to know messaging details.
+ *
+ * A key concept for this is that your plugin should use a particular "portnum" for each message type you want to receive
+ * and handle.
+ *
+ * Interally we use plugins to implement the core meshtastic text messaging and gps position sharing features.  You
+ * can use these classes as examples for how to write your own custom plugin.  See here: (FIXME)
+ */
+class MeshPlugin
+{
+    const char *name;
+
+    static std::vector<MeshPlugin *> plugins;
+
+  public:
+    /** Constructor
+     * name is for debugging output
+     */
+    MeshPlugin(const char *_name);
+
+    virtual ~MeshPlugin();
+
+    /**
+     * Initialize your plugin.  This setup function is called once after all hardware and mesh protocol layers have
+     * been initialized
+     */
+    virtual void setup() {}
+
+    /**
+     * @return true if you want to receive the specified portnum
+     */
+    virtual bool wantPortnum(PortNum p) = 0;
+
+    /** Called to handle a particular incoming message
+
+    @return true if you've guaranteed you've handled this message and no other handlers should be considered for it
+    */
+    virtual bool handleReceived(const MeshPacket &mp) { return false; }
+
+    /** For use only by MeshService 
+     */
+    static void callPlugins(const MeshPacket &mp);
+};