Add NoteService to handle note operations

NoteService should be the only class with access to NoteDao;
nowhere else should NoteDao be accessed directly.

Channel dependencies are static in PacketProcessor, for now.
Ideally they would be injected in the constructor,
but since the constructor is private and I don't want to open
up that can of worms, I'll leave it like this.
At the very least, now we have a way of injecting services into
the handlers. This will make further restructuring way easier.

src/main/java/service/NoteService.java

@@ -0,0 +1,93 @@
+package service;
+
+import client.Character;
+import database.DaoException;
+import database.note.NoteDao;
+import model.Note;
+import net.packet.Packet;
+import net.server.Server;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import tools.PacketCreator;
+
+import java.util.List;
+import java.util.Optional;
+
+public class NoteService {
+    private static final Logger log = LoggerFactory.getLogger(NoteService.class);
+
+    private final NoteDao noteDao;
+
+    public NoteService(NoteDao noteDao) {
+        this.noteDao = noteDao;
+    }
+
+    /**
+     * Send normal note from one character to another
+     *
+     * @return Send success
+     */
+    public boolean sendNormal(String message, String senderName, String receiverName) {
+        Note normalNote = Note.createNormal(message, senderName, receiverName, Server.getInstance().getCurrentTime());
+        return send(normalNote);
+    }
+
+    /**
+     * Send note which will increase the receiver's fame by one.
+     *
+     * @return Send success
+     */
+    public boolean sendWithFame(String message, String senderName, String receiverName) {
+        Note noteWithFame = Note.createGift(message, senderName, receiverName, Server.getInstance().getCurrentTime());
+        return send(noteWithFame);
+    }
+
+    private boolean send(Note note) {
+        try {
+            NoteDao.save(note);
+            return true;
+        } catch (DaoException e) {
+            log.error("Failed to send note {}", note, e);
+            return false;
+        }
+    }
+
+    /**
+     * Show unread notes
+     *
+     * @param chr Note recipient
+     */
+    public void show(Character chr) {
+        if (chr == null) {
+            throw new IllegalArgumentException("Unable to show notes - chr is null");
+        }
+
+        final List<Note> notes;
+        try {
+            notes = noteDao.findAllByTo(chr.getName());
+        } catch (DaoException e) {
+            log.error("Failed to find notes sent to chr name {}", chr.getName(), e);
+            return;
+        }
+
+        Packet showNotesPacket = PacketCreator.showNotes(notes);
+        chr.sendPacket(showNotesPacket);
+    }
+
+    /**
+     * Discard a read note
+     *
+     * @param id Id of note to discard
+     * @return Discarded note. Empty optional if failed to discard.
+     */
+    public Optional<Note> discard(int id) {
+        try {
+            return noteDao.delete(id);
+        } catch (DaoException e) {
+            log.error("Failed to discard note with id {}", id, e);
+            return Optional.empty();
+        }
+    }
+
+
+}