[Bleeding] Added Conversations API. Addresses BUKKIT-864

By: rmichela <deltahat@gmail.com>

paper-api/src/main/java/org/bukkit/conversations/PluginNameConversationPrefix.java

@@ -0,0 +1,39 @@
+package org.bukkit.conversations;
+
+import org.bukkit.ChatColor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.plugin.Plugin;
+
+/**
+ * PluginNameConversationPrefix is a {@link ConversationPrefix} implementation that displays the plugin name in front of
+ * conversation output.
+ */
+public class PluginNameConversationPrefix implements ConversationPrefix {
+    
+    protected String separator;
+    protected ChatColor prefixColor;
+    protected Plugin plugin;
+    
+    private String cachedPrefix;
+    
+    public PluginNameConversationPrefix(Plugin plugin) {
+        this(plugin, " > ", ChatColor.LIGHT_PURPLE);
+    }
+    
+    public PluginNameConversationPrefix(Plugin plugin, String separator, ChatColor prefixColor) {
+        this.separator = separator;
+        this.prefixColor = prefixColor;
+        this.plugin = plugin;
+
+        cachedPrefix = prefixColor + plugin.getDescription().getName() + separator + ChatColor.WHITE;
+    }
+
+    /**
+     * Prepends each conversation message with the plugin name.
+     * @param context Context information about the conversation.
+     * @return An empty string.
+     */
+    public String getPrefix(ConversationContext context) {
+        return cachedPrefix;
+    }
+}