Based on the excelent feedback from @MaartenBaert in #6 this PR improves some aspects of the post-processing logic:

• add new generic NUM_RAW_BITS to configure the number of raw random bits that get sampled in order to generate one final output byte (has to be a power of two)
• add a more elaborated sampling unit to improve entropy compression (based on CRC-8)

• minor code and documentation cleanups
• add GitHub actions workflow (for testing the simulation mode)
• replace explicit propagation delay by a simple flip flop (simulation mode-only)

A cleaned-up version with more understandable code.

All-new design 🚀

• smaller hardware footprint
• simpler configuration (less generics)
• better documentation
• improved random quality

🚀 The all-new neoTRNG v2