Improve JavaFX getting started experience

[jdneo]

Tasks for consideration:

• Provide VS Code samples in https://github.com/openjfx/samples
• Add VS Code JavaFX section in https://openjfx.io/openjfx-docs/ or our own document site
  - Our own doc: https://code.visualstudio.com/docs/java/java-gui
  - Official document: Provide getting started document for VS Code openjfx/openjfx-docs#214
• Support creating JavaFX projects

[Eskibear]

Highlight JavaFX Maven Archetype when creating a new Maven project

First page of archetypes are hardcoded for the moment, let me know if you want to add one for javafx