Minor cleanup using inspections + Https

* Use https for maven repositories if possible
* Fix typos
* Merge ProtocolLib listeners into one class
* Upgrade maven plugins and dependencies

universal/pom.xml

@@ -22,7 +22,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-shade-plugin</artifactId>
-                <version>2.4.3</version>
+                <version>3.0.0</version>
                 <configuration>
                     <createDependencyReducedPom>false</createDependencyReducedPom>
                     <shadedArtifactAttached>false</shadedArtifactAttached>
@@ -43,15 +43,6 @@
                     </execution>
                 </executions>
             </plugin>
-
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-jar-plugin</artifactId>
-                <version>3.0.2</version>
-                <configuration>
-                    <outputDirectory>${outputDir}</outputDirectory>
-                </configuration>
-            </plugin>
         </plugins>
     </build>