Restructured project to conform with CSCE361 convention.

-   Changed the project's package and made corresponding changes to
    `pom.xml` and `Chat.java`
-   Added `.gitkeep`s to `src/test` and `src/main/resources` so they're
    available to prompt students
-   closes #1

pom.xml

@@ -4,7 +4,7 @@
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
-    <groupId>edu.unl.cse</groupId>
+    <groupId>edu.unl.cse.csce361.socket_chat</groupId>
     <artifactId>SocketChat</artifactId>
     <version>1.0-SNAPSHOT</version>
     <build>
@@ -24,7 +24,7 @@
                     <archive>
                         <manifest>
                             <addClasspath>true</addClasspath>
-                            <mainClass>edu.unl.cse.socketchat.Chat</mainClass>
+                            <mainClass>edu.unl.cse.csce361.socket_chat.Chat</mainClass>
                         </manifest>
                     </archive>
                 </configuration>

src/main/java/edu/unl/cse/socketchat/Chat.java → src/main/java/edu/unl/cse/csce361/socket_chat/Chat.java

-/*
- * Copyright (c) 2019 Christopher A. Bohn, bohn@unl.edu.
- */
-
-package edu.unl.cse.socketchat;
+package edu.unl.cse.csce361.socket_chat;
 
 import java.io.*;
 import java.net.InetAddress;