Adding all levels + linking buttons

to create new level just do

`gradle -q --console plain -PmainClass=school_project.Parsers.FileParserFactory run`

Co-authored-by: Anthony Debucquoy <debucquoy.anthony@gmail.com>
Reviewed-on: #56
Reviewed-by: Mat_02 <diletomatteo@gmail.com>

app/build.gradle

@@ -29,7 +29,7 @@ dependencies {
 
 application {
     // Define the main class for the application.
-    mainClass = 'school_project.Controller'
+    mainClass = project.hasProperty("mainClass") ? project.getProperty("mainClass") : 'school_project.Controller'
 }
 
 javafx {
@@ -41,3 +41,7 @@ tasks.named('test') {
     // Use JUnit Platform for unit tests.
     useJUnitPlatform()
 }
+
+run{
+standardInput = System.in
+}