Add Options-Menu-Entry

[Quimoniz]

Extend landing page with an 'Options' button.

Therein allow for some configuration options (e.g. how the Protagonist ship flies to the mouse, or if player wants to only use arrow-keys).

Add the ability to have more - hidden Configuration options - which only make sense for the developer (e.g. choose among all available MapGenerators even those who are broken, show collision/bounding-boxes, enable invincibility, perhaps a 'textarea' to adjust JSON with spawn rates for multiple enemies...).