Update checkstyle config and CodeClimate exclusions

- Add new checkstyle checks: require Javadoc on large private methods, default in switch, declaration order & others
- Update path exclusions in CodeClimate config to match newly renamed classes (e.g. PHPBB -> PhpBB)
  - Create consistency check testing that excluded paths exist as classes
- Fix some trivial violations

src/test/java/fr/xephi/authme/command/executable/HelpCommandTest.java

@@ -26,7 +26,7 @@ import static fr.xephi.authme.command.help.HelpProvider.SHOW_COMMAND;
 import static fr.xephi.authme.command.help.HelpProvider.SHOW_DESCRIPTION;
 import static java.util.Arrays.asList;
 import static java.util.Collections.singletonList;
-import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.Matchers.containsString;
 import static org.junit.Assert.assertThat;
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.BDDMockito.given;

src/test/java/fr/xephi/authme/command/executable/authme/debug/DebugSectionConsistencyTest.java

@@ -1,6 +1,7 @@
 package fr.xephi.authme.command.executable.authme.debug;
 
 import fr.xephi.authme.ClassCollector;
+import fr.xephi.authme.TestHelper;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
@@ -22,8 +23,8 @@ public class DebugSectionConsistencyTest {
 
     @BeforeClass
     public static void collectClasses() {
-        debugClasses = new ClassCollector("src/main/java", "fr/xephi/authme/command/executable/authme/debug")
-            .collectClasses();
+        debugClasses = new ClassCollector(
+            TestHelper.SOURCES_FOLDER, TestHelper.PROJECT_ROOT + "command/executable/authme/debug").collectClasses();
     }
 
     @Test