Remove JavaFX dependency

[rnayabed]

Fix #198

While using this plugin, it ignores the user specified JavaFX version and uses the one that this depends on (in this case, 16.0.1 depends on JavaFX 16).

Currently, one needs to do the following in order to use their own specific JavaFX version :

<dependency>
  <groupId>eu.hansolo</groupId>
  <artifactId>medusa</artifactId>
  <version>16.0.1</version>
  <exclusions>
    <exclusion>
      <groupId>org.openjfx</groupId>
      <artifactId>*</artifactId>
    </exclusion>
  </exclusions>
</dependency>

This is the same approach used in ControlsFX

[rnayabed]

@HanSolo thoughts?

[rnayabed]

@HanSolo ???