Enabled PMD checking for jsp files

2 rulesets are included.

airsonic-main/pom.xml

@@ -595,6 +595,24 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-checkstyle-plugin</artifactId>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-pmd-plugin</artifactId>
+                <configuration>
+                    <language>jsp</language>
+                    <rulesets>
+                        <ruleset>/category/jsp/codestyle.xml</ruleset>
+                        <ruleset>/category/jsp/errorprone.xml</ruleset>
+                    </rulesets>
+                    <includes>
+                        <include>**/*.jsp</include>
+                        <include>**/*.jspf</include>
+                    </includes>
+                    <compileSourceRoots>
+                        <compileSourceRoot>${basedir}/src/main/webapp/WEB-INF/jsp</compileSourceRoot>
+                    </compileSourceRoots>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-maven-plugin</artifactId>

pom.xml

@@ -264,6 +264,23 @@
                         </dependency>
                     </dependencies>
                 </plugin>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-pmd-plugin</artifactId>
+                    <version>3.12.0</version>
+                    <executions>
+                        <execution>
+                            <id>validate</id>
+                            <phase>validate</phase>
+                            <configuration>
+                                <sourceEncoding>utf-8</sourceEncoding>
+                            </configuration>
+                            <goals>
+                                <goal>check</goal>
+                            </goals>
+                        </execution>
+                    </executions>
+                </plugin>
                 <plugin>
                     <groupId>org.owasp</groupId>
                     <artifactId>dependency-check-maven</artifactId>