Avoid these compilation errors:
```
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] /tmp/app/webgoat-lessons/command-injection/src/main/java/org/owasp/webgoat/plugin/CommandInjectionExecute.java:[47,8] class HttpBasicsInterceptRequest is public, should be declared in a file named HttpBasicsInterceptRequest.java
[ERROR] /tmp/app/webgoat-lessons/command-injection/src/main/java/org/owasp/webgoat/plugin/CommandInjection.java:[38,8] class HttpProxies is public, should be declared in a file named HttpProxies.java
[ERROR] /tmp/app/webgoat-lessons/command-injection/src/main/java/org/owasp/webgoat/plugin/CommandInjection.java:[5,33] cannot find symbol
symbol: class AbstractLesson
location: package org.owasp.webgoat.lessons
[ERROR] /tmp/app/webgoat-lessons/command-injection/src/main/java/org/owasp/webgoat/plugin/CommandInjection.java:[38,34] cannot find symbol
symbol: class AbstractLesson
[ERROR] /tmp/app/webgoat-lessons/command-injection/src/main/java/org/owasp/webgoat/plugin/CommandInjection.java:[39,5] method does not override or implement a method from a supertype
[ERROR] /tmp/app/webgoat-lessons/command-injection/src/main/java/org/owasp/webgoat/plugin/CommandInjection.java:[44,5] method does not override or implement a method from a supertype
[ERROR] /tmp/app/webgoat-lessons/command-injection/src/main/java/org/owasp/webgoat/plugin/CommandInjection.java:[49,5] method does not override or implement a method from a supertype
[ERROR] /tmp/app/webgoat-lessons/command-injection/src/main/java/org/owasp/webgoat/plugin/CommandInjection.java:[54,5] method does not override or implement a method from a supertype
[ERROR] /tmp/app/webgoat-lessons/command-injection/src/main/java/org/owasp/webgoat/plugin/CommandInjection.java:[59,5] method does not override or implement a method from a supertype
[INFO] 9 errors
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.356 s
[INFO] Finished at: 2019-10-19T21:13:03Z
[INFO] ------------------------------------------------------------------------
```
- Now using Spring Boot for classloading, this way local development does not need to restart the complete server
- Fixed all kinds of dependencies on the names of the lessons necessary to keep in mind during the creation of a lesson.
- Simplied loading of resources, by adding resource mappings in MvcConfig.
- Refactored plugin loading, now only one class is left for loading the lessons.
