allow to create static lib for javafx.media on linux

There are a few issues preventing the static build of the JavaFX media files on linux (libjfx.media.a), and use it in a statically linked context:

* gststreamer plugins need to be registered statically

* symbol duplications need to be avoided

* the "resource" protocol in URL's created for bundled resources with GraalVM native-image is not supported.